37 Replies Latest reply: Jul 6, 2012 2:03 AM by bob frost RSS

    LR4.1--Is there a way to speed up 1:1 "zoom?"

    dpick2 Community Member

      I use Canon 7D dng files.  When I zoom to 1:1, it takes about 7 seconds to render the view.  When going through 200-300 images to check focus, obviously this adds greatly to the time.  I use one 24" monitor @ 1920x1200, and if I make the image display area as small as possible, it still takes about 6.5 seconds to render the view (loading...). 

       

      Is there a way to make this faster?  Can I preload zoomed images into the database for a collection of photos?  I love LR, and I'm not interested in bashing the product.  I just want to maximize its potiential.  Also, I know that the "Lightroom is slow" thread discusses 1:1 preview.  I just wanted to ask this question specifically as to not make it a part of a general complaint about LR. 

       

      Thank you.

       

      Win7 x64

      i7 intel CPU running @4.2ghz

      16gigs RAM

      SSD primary drive

      4 2T hard drives

        • 1. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
          Victoria_Bampton CommunityMVP

          Have you rendered 1:1 previews in advance?  If not, select all the photos in Grid view and go to Library menu > Previews > Render 1:1 Previews and wait for it to finish. 

          • 2. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
            Bob_Peters Community Member

            Victoria Bampton wrote:

             

            Have you rendered 1:1 previews in advance?  If not, select all the photos in Grid view and go to Library menu > Previews > Render 1:1 Previews and wait for it to finish. 

             

            I sem to recall hearing the OP's comment at some time in the recent past

             

            Allow me to ask you one of my favorite questions:  After you render your 1:1 previews how many cores are active when you zoom to 1:1 view in the Library.  I will boldly predict that only 1 core is active at any given time while zooming.

            • 3. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
              Ian Lyons CommunityMVP

              Since the photo has already been rendered Lr only needs to load it. Why would this require more than one core?

              • 4. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                Bob_Peters Community Member

                Ian Lyons wrote:

                 

                Since the photo has already been rendered Lr only needs to load it. Why would this require more than one core?

                 

                That's an easy one to answer:  Beause zooming to 1:1 takes much too long.  That is, a number of seconds.  The image should "snap" to 1:1 within a second.  Take a look, for example, at Corel AfterShot (formerly Bibble Pro).

                • 5. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                  Ian Lyons CommunityMVP

                  Bob_Peters wrote:

                   

                  That's an easy one to answer:  Beause zooming to 1:1 takes much too long.  That is, a number of seconds.  The image should "snap" to 1:1 within a second.  Take a look, for example, at Corel AfterShot (formerly Bibble Pro).

                   

                   

                  Hmm, it takes around a second to zoom on 3 Mac systems I have here. That being said, the behaviour (i.e. animated zoom) is as per design (i.e  another BS feature that have Adobe loaded Lr with for years, all with the purpose of enhancing the user experience <cough>). You want to check compare how fast ACR displays spot heals compared to Lr (yep, more animation).

                  • 6. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                    Bob_Peters Community Member

                    Ian Lyons wrote:

                     

                    Bob_Peters wrote:

                     

                    That's an easy one to answer:  Beause zooming to 1:1 takes much too long.  That is, a number of seconds.  The image should "snap" to 1:1 within a second.  Take a look, for example, at Corel AfterShot (formerly Bibble Pro).

                     

                     

                    Hmm, it takes around a second to zoom on 3 Mac systems I have here. That being said, the behaviour (i.e. animated zoom) is as per design (i.e  another BS feature that have Adobe loaded Lr with for years, all with the purpose of enhancing the user experience <cough>). You want to check compare how fast ACR displays spot heals compared to Lr (yep, more animation).

                     

                    I only have access to 2 Mac systems at the present time, both running OS X (10.7.4)

                     

                    MacPro 1,1 (creaky old):  around 4 seconds to zoom to 1:1 in the library or go to the next image at 1:1.

                    MacBook Pro (retina display):  roughly the same amount of time for the same operations noted above.

                     

                    On the other hand the MacBook Pro computes the 1:1 previews in half the time required by the MacPro.  And zooming to 1:1 in the Develop module is much faster than zooming in the Library module on both computers.

                     

                    I made the same observations on a "new" 2012, 3.33GHz, 6-core MacPro before returning it to Apple.  Too little bang for the buck!

                     

                    The reason the time to traverse a few images at 1:1 is important is because I am fine-tuning the auto-focus of several lenses on a Nikon D800.  Having to wait several seconds to go from one image to the next is a pain in the rear.  I finally had to resort to loading 1:1 JPEG files into CS5 and checking the focus shift there.

                     

                    I am more and more convinced that Lightroom is not as fast as it should be.  No, I have no idea why since I'm on the outside looking in and my training is in a field far removed from software.

                     

                    There are faster raw processors on the market (I already mentioned one.) but I do not want to ditch Lightroom.

                    • 7. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                      Gavin Farrington Community Member

                      Consider taking a look at PhotoMechanic by CameraBits for this specific usage.  It's ridiculously fast.  I'm a wedding and event photog, and with the volume of images I have to deal with, PM is where I always do my first pass of culling before I go to LR.

                       

                      LR always works from previews.  PM works from the JPG that's embedded inside the RAW file by the camera.  Since there's nothing to process or render (other than loading the embedded JPG) it really screams, even on old antiquated hardware.  There are advantages and disadvantages to both methods, but when speed is of the essence I can't recommend PM enough.

                       

                      Some of the regulars in this thread have asked the LR team to give LR the ability to work from that embeded data for this very purpose.  Hopefully we'll see that request filled one day.  Until then, look at PM.

                      • 8. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                        areohbee Community Member

                        It's not inherently faster to work from a preview computed by the camera and embedded in the raw, than a preview computed by Lr and stored separately on disk.

                         

                        1:1 zoom takes *way* less than a second for me (e.g. D300). And stepping from image to image is nearly instantaneous (image display-wise. histogram, metadata, and info display lag a bit). That's *if* the requisite view is available. Granted it would take longer to zoom 1:1 if camera is D800, but multiple seconds means something not right.

                         

                        I think it's worth keeping in mind that some people are experiencing abnormally bad performance.

                         

                        R

                        • 9. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                          Bob_Peters Community Member

                          The stuff in lrdata does not look at all like a jpeg.  I'm guessing it's some intermediate form between NEF and JPEG...don't know what.

                           

                          So it's not at all obvious that the imbedded JPEG access should not be faster.

                          • 10. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                            areohbee Community Member

                            Bob_Peters wrote:

                             

                            The stuff inlrdata does not look at all like a jpeg.

                             

                            lrprev files are 1-7 jpegs (image data - no metadata) end-to-end with some garnish.

                             

                            Download preview-exporter source code if you want to understand in greater detail.

                             

                            R

                            • 11. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                              Bob_Peters Community Member

                              No thanks.  I'll take that on faith.

                               

                              Sent from my iPad

                              • 12. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                DdeGannes Community Member

                                The original post was made almost 9 hours ago and he has not commented on the several reply to his post. I am a bit perplexed since to OP did not indicate whether he in working in the Library Module or the Develop Module. If he is working in the Develop Module then building 1:1 previews will not help.

                                • 13. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                  areohbee Community Member

                                  Fair enough.

                                   

                                  Regarding core usage. The reason only one core is needed to load a preview is that the disk can only be accessed sequentially, and one core is faster than the disk. So, for operations that are disk-bound, like loading previews, more cores won't help. Rendering previews is another matter, since that is cpu-limited, not disk.

                                   

                                  Note: all of this assumes Lr is behaving normally, which it may not be.

                                   

                                  R

                                  • 14. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                    areohbee Community Member

                                    Rendering 1:1 previews may help a little, since it creates the ACR cache info, but my experience has also been that it helps *very* little.

                                     

                                    That said, the first time one goes to 1:1 in Develop module it will always take multiple seconds. That's a design trait: rendering takes seconds and occurs on demand.

                                     

                                    After the first time, it should be much quicker, since the info is subsequently cached efficiently in ram. At this stage, the operation is cpu bound, and should use all cores.

                                     

                                    R

                                    • 15. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                      Bob_Peters Community Member

                                      Rob Cole wrote:

                                       

                                      Fair enough.

                                       

                                      Regarding core usage. The reason only one core is needed to load a preview is that the disk can only be accessed sequentially, and one core is faster than the disk. So, for operations that are disk-bound, like loading previews, more cores won't help. Rendering previews is another matter, since that is cpu-limited, not disk.

                                       

                                      Note: all of this assumes Lr is behaving normally, which it may not be.

                                       

                                      R

                                       

                                      Correct.  Only one core is needed.  One core is all that is needed for any Lightroom operation.

                                       

                                      I am loading the preview images from a 512GB SSD.  Do you really think that takes a significant amount of time?  This SSD has been clocked by Lloyd Chambers (http://macperformanceguide.com/mbpRetina2012-speed-ssd.html) at more that 400 MB/sec read speed.  Based on that measurement, reading a 25MB, D800 JPEG generated by Lightroom would take about 0.06 seconds.  How is the remainder of the time being utilized?

                                       

                                      I am using a quad-core i7 with hyper-threading so there is absolutely no reason why those cores should not participate in the display of the image.  Again, just as an illustration, Corel AfterShot Pro uses all cores when zooming a preview to 1:1.  Photoshop CS5 uses all cores when zooming from 12.5% to 100%.  After that point the image has been chached (I assume) because zooming operationsdon't generate such obvious cpu-core activity.

                                       

                                      Why shouldn't/can't Lightroom perform just as fast?

                                      • 16. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                        dpick2 Community Member

                                        Thanks to all who have responed.  Yes, the time lag is, indeed, in Library mode.  When using Develope mode, it takes about 2.5 seconds for a 1:1.  So, that's much better.  However, when initially going through images, I use Grid mode and Compare quite often, so I'm stuck with very slow speeds of Library ("compare" is a real hair puller, sometimes).

                                         

                                        Thank you, Victoria, for the the advice on pre-rendering 1:1--that's the feature I was needing.  However, I have had issues with looking at images where I have already viewed in 1:1 and come back at a later point and still had to wait while a the image was rendered.  I'll clear the cach to see if that helps.  And, really, DdeGannes, concerned about 9 hours during the day on July 4th?  I was enjoying a hot dog (or two).

                                         

                                        Thanks again to all.

                                         

                                        Edit: Victoria, you saved me.  That works perfectly.  I don't mind starting the task and coming back when finished.  I tried it on a folder with 150 images, and it took 11:50 to complete, which is about 4.6 seconds an image.  So, it went faster than rendering individually.  Plus, I can do something in 12 minutes while a group of photos render.  However, doing it "on the fly" leaves only waiting for the "loading...." to stop.  I never knew this feature was there (it is rather hidden), and thanks again for the help.

                                        • 17. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                          dpick2 Community Member

                                          When pre-rendering my folder of 150 images, all 8 cores were active (4 real, 4 "not so real").  The cores were not "pegged," but they were all active--around 60-70%.

                                          • 18. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                            areohbee Community Member

                                            One core is all that can possibly be used (advantageously) to load the image from disk, unless newest SSD's are multiported and I'm not up-to-date about it (?). If one core doesn't have enough oomph to simultaneously decompress it while loading, then other cores could participate advantageously. What else Lr is doing and why things can take so long is beyond me.

                                            • 19. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                              areohbee Community Member

                                              Yes, rendering should use all cores. Why they're not pegged at 100% is another mystery to me. In an ideal world, it would mean that there was nothing more for them to do, (i.e. other bottle-necks were constraining throughput, not CPU), but I'm not sure how ideal the world is... - as Bob Peters pointed out, if the disk were the constraint, then it would be much faster, especially SSD. I really don't have a clue.

                                              • 20. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                dpick2 Community Member

                                                Rob Cole wrote:

                                                 

                                                One core is all that can possibly be used (advantageously) to load the image from disk, unless newest SSD's are multiported and I'm not up-to-date about it (?). If one core doesn't have enough oomph to simultaneously decompress it while loading, then other cores could participate advantageously. What else Lr is doing and why things can take so long is beyond me.

                                                Agree.  Retrieving from disk is an instruction, not a calculation.  However, why such computing power is engaged to render a 1:1 image is beyond me.  An (over-clocked) i7 is a pretty impressive piece of hardware, plus I have a GeForce 560Ti GPU which could do the job quite nicely, too.  When playing a 3D game, every image is rendered moment by moment @ 1920x1200.  I have no idea why 7 seconds (or, 4.6 in a batch) is needed to render a 1:1 image.  I'm no programming or computer scientist, so honestly it baffles me why it takes so long.

                                                • 21. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                  areohbee Community Member

                                                  3D games use vector graphics and card plays a huge roll in performance.

                                                   

                                                  2D Lightroom uses bitmapped graphics, and 99.9% of the time is in computing the bitmap (when rendering) from raw camera data.

                                                   

                                                  i7 is a powerful machine, but Lr uses very sophisticated algorithms for maximizing quality.

                                                   

                                                  I really have no detailed understanding of the technology, but generally - that's the deal.

                                                   

                                                  That may explain rendering time, other things: not so much.

                                                   

                                                  PS - Lightroom does use all cores (or should anyway) when zooming to 1:1 when image is already loaded because operation is once again CPU bound.

                                                   

                                                  R

                                                  • 22. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                    Bob_Peters Community Member

                                                    Rob Cole wrote:

                                                     

                                                     

                                                    PS - Lightroom does use all cores (or should anyway) when zooming to 1:1 when image is already loaded because operation is once again CPU bound.

                                                     

                                                    R

                                                     

                                                    No, Rob.  On the 4 Macs I had access to Lightoom never used more than a single core at one time whem szooming an existing 1:1 preview to 1:1 in the Library module.  As I already said in post #6 I now have access to just 2 Mac systems:  a MacPro 1,1 (old!) and a new MacBook Pro "retina" (4-core i7).

                                                    • 23. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                      areohbee Community Member

                                                      I think in library view it's always getting preview from disk and displaying it (assuming preview is available on disk and need not be re-rendered), whereas in develop view it's getting it from ram (after loading I mean). Thus the difference.

                                                      • 24. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                        ssprengel Community Member

                                                        Isn’t there a “database” associated with previews so part of LR’s slowness could be it figuring out exactly where the preview data is and comparing it with the last time the image was modified, more than loading the preview data once it knows?  Another variable might be how much of the LR and LR-preview database is currently cached in memory vs needing to be loaded from the disk/SSD.  The number of previews in the LR database would have an effect on this, and I remember people having issues using a converted previews database where things dramatically sped up when the older LR3 preview/preview-database (the entire previews-related folder) was deleted and LR4 rebuilt it, almost as if the structure of the database was different in LR4 but LR4 could use the LR3 preview data in some slower compatibility mode, though perhaps it is just the size of the database being small when LR first starts to build it from scratch.  Finally, I would imagine that having auto-XMP writing turned on is distracting for LR in terms of speed and resource usage that can also affect speed.

                                                        • 25. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                          areohbee Community Member

                                                          Hi Steve,

                                                           

                                                          Yes, it's worth making the distinction "this assumes Lightroom functioning normally".

                                                           

                                                          Preview files are raw (jpeg) image data, preview database has the info needed to display them properly.

                                                           

                                                          If database is wonky, or accessing it is problematic for some reason, that could cause abnormal performance.

                                                           

                                                          If Lr functioning normally, the database access and associated computations should be very fast.

                                                           

                                                          I have no idea all the ways Lightroom could get confused and take excessive time. I would think auto-writing of xmp should not interfere significantly, but when there are bugs, all bets are off...

                                                           

                                                          R

                                                          • 26. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                            ssprengel Community Member

                                                            I would think that to avoid corruption in a single-user environment which LR is, database accesses are single threaded so if the auto-XMP writing is working on an image and especially if actually updating something, perhaps the previews database or regular LR database operation is queued behind it and delayed w/o any obvious reason.   And a background operation that reads through the database and many files to see if they’re up-to-date or not, would tend to flush other useful data from the disk-cache prematurely, causing LR to re-read information from disk that it wouldn’t if nothing else was going on.

                                                            • 27. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                              areohbee Community Member

                                                              I dunno Steve. writing xmp involves reading catalog and writing xmp file. displaying previews involves reading preview database (not catalog), and reading preview image data. I would expect asynchronous threads doing each of those tasks.

                                                               

                                                              Although I can certainly imagine delays if preview request happened while xmp write in progress (or even afterward due to the kind of stuff you were talking about), I would expect them to be very short. Also, if xmp disk and preview disk are different then I would expect simultuaneous disk access, otherwise sequential disk access would be required, which could delay preview display a smidge.

                                                               

                                                              FWIW, I always recommend people turn off auto-write xmp, just to eliminate all possibility that it ever interferes with anything, at least until Lr is performing like a well-oiled machine, if not forever...

                                                               

                                                              Note: xmp will only be written after a change, so to have it interfere with 1:1 zoom, one would have to zoom immediately after making a change...

                                                              • 28. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                bob frost Community Member

                                                                Bob_Peters wrote:

                                                                 

                                                                I am loading the preview images from a 512GB SSD.  Do you really think that takes a significant amount of time?  This SSD has been clocked by Lloyd Chambers (http://macperformanceguide.com/mbpRetina2012-speed-ssd.html) at more that 400 MB/sec read speed.  Based on that measurement, reading a 25MB, D800 JPEG generated by Lightroom would take about 0.06 seconds.  How is the remainder of the time being utilized?

                                                                 

                                                                I am using a quad-core i7 with hyper-threading so there is absolutely no reason why those cores should not participate in the display of the image.  Again, just as an illustration, Corel AfterShot Pro uses all cores when zooming a preview to 1:1.  Photoshop CS5 uses all cores when zooming from 12.5% to 100%.  After that point the image has been chached (I assume) because zooming operationsdon't generate such obvious cpu-core activity.

                                                                 

                                                                Why shouldn't/can't Lightroom perform just as fast?

                                                                 

                                                                 

                                                                On my fast PC (six cores, SandyBridgeE) moving from one D800 nef to another in Library is instantaneous at 1:1, providing I have built the 1:1 previews previously. No lag whatsoever, no 'loading', the screen view just changes immediately I press the arrow button to move to the next image. So it is not that LR 'can't' do it, it does on my machine. Now you are using a Mac, so that is one variable, and the Mac version of LR is the other variable.

                                                                 

                                                                Bob Frost

                                                                • 29. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                  areohbee Community Member

                                                                  In case you don't already know, you can have 1:1 previews rendered upon import too.

                                                                   

                                                                  And, you don't have to wait for it to finish, before you can start taking advantage of it - as soon as the first one renders, you can zoom it quickly to 1:1, while the next is being rendered...

                                                                   

                                                                   

                                                                  dpick2 wrote:

                                                                   

                                                                  However, I have had issues with looking at images where I have already viewed in 1:1 and come back at a later point and still had to wait while a the image was rendered.

                                                                   

                                                                  If you change settings via quick-develop, or develop module, 1:1 lib preview will need to be re-rendered next time you visit in lib (this assumes Lr functioning normally. If there is a bug, it may decide to re-render again needlessly).

                                                                   

                                                                  I think there is room for improvement assuring lib previews are up2date. For example, lib preview could be marked for update when changes are made that will cause a re-loading. And then, photos so marked could be updated in the background.

                                                                  • 30. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                    Bob_Peters Community Member

                                                                    bob frost wrote:

                                                                     

                                                                    Bob_Peters wrote:

                                                                     

                                                                    I am loading the preview images from a 512GB SSD.  Do you really think that takes a significant amount of time?  This SSD has been clocked by Lloyd Chambers (http://macperformanceguide.com/mbpRetina2012-speed-ssd.html) at more that 400 MB/sec read speed.  Based on that measurement, reading a 25MB, D800 JPEG generated by Lightroom would take about 0.06 seconds.  How is the remainder of the time being utilized?

                                                                     

                                                                    I am using a quad-core i7 with hyper-threading so there is absolutely no reason why those cores should not participate in the display of the image.  Again, just as an illustration, Corel AfterShot Pro uses all cores when zooming a preview to 1:1.  Photoshop CS5 uses all cores when zooming from 12.5% to 100%.  After that point the image has been chached (I assume) because zooming operationsdon't generate such obvious cpu-core activity.

                                                                     

                                                                    Why shouldn't/can't Lightroom perform just as fast?

                                                                     

                                                                     

                                                                    On my fast PC (six cores, SandyBridgeE) moving from one D800 nef to another in Library is instantaneous at 1:1, providing I have built the 1:1 previews previously. No lag whatsoever, no 'loading', the screen view just changes immediately I press the arrow button to move to the next image. So it is not that LR 'can't' do it, it does on my machine. Now you are using a Mac, so that is one variable, and the Mac version of LR is the other variable.

                                                                     

                                                                    Bob Frost

                                                                     

                                                                    Wow! That's impressive.  I wish I had that much "horsepower"!

                                                                    • 31. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                      areohbee Community Member

                                                                      Wow! That's impressive.  I wish I had that much "horsepower"!

                                                                       

                                                                      Even if you don't, the lag should be a fraction of a second, not multiple seconds. If the latter, then you're being bitten by a bug.

                                                                       

                                                                      Put previews on fast drive to minimize delay. It's the drive more than the CPU that limits speed in library sequencing, the opposite is true in Develop mode (assuming normal functioning).

                                                                      • 32. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                        Bob_Peters Community Member

                                                                        Rob Cole wrote:

                                                                         

                                                                        Wow! That's impressive.  I wish I had that much "horsepower"!

                                                                         

                                                                        Even if you don't, the lag should be a fraction of a second, not multiple seconds. If the latter, then you're being bitten by a bug.

                                                                         

                                                                        Put previews on fast drive to minimize delay. It's the drive more than the CPU that limits speed in library sequencing, the opposite is true in Develop mode (assuming normal functioning).

                                                                        Rob:

                                                                         

                                                                        Please go back a few posts and read what I wrote:  I'm using a very fast, 512 GB SSD.

                                                                        • 33. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                          areohbee Community Member

                                                                          Reply was for other readers too.

                                                                          • 34. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                            LRuser24 Community Member

                                                                            Rob Cole wrote:

                                                                             

                                                                            One core is all that can possibly be used (advantageously) to load the image from disk (...)

                                                                            Not necessarily. Preview images are compressed (JPEG if I remember correctly), and they must be decompressed to be displayed. Furthermore, when browsing back and forth, preview files will be in the file system cache of the OS, so the file loading can become effectively CPU-bound and consequently very fast compared to the decompression. Because JPEG decompression can be nicely parallelized, preview loading *can* benefit from multiple cores - depending on how fast the file reading is compared to the decompression (which depends on the preview dimensions). I can imagine that this may be even the case for loading from a fast disk (not cached) and large (>20MP) 1:1 previews.

                                                                             

                                                                            And it seems that LR already uses multiple threads when loading previews: Render some 1:1 previews for large images, and then browse in loupe mode in 1:1 view (ok, that does not make real sense)... you will see that more than 1 core is used in sum.

                                                                             

                                                                            *However*: When browsing in "fit" mode, LR uses the standard previews which decompress much faster, so parallelization will probably hardly make any difference. Note: Standard preview size must be set so the previews are large enough for the monitor, or else LR will fall back to 1:1 previews which will be slower, even if rendered in advance.

                                                                            • 35. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                              Bob_Peters Community Member

                                                                              LRuser24 wrote:

                                                                               

                                                                              And it seems that LR already uses multiple threads when loading previews: Render some 1:1 previews for large images, and then browse in loupe mode in 1:1 view (ok, that does not make real sense)... you will see that more than 1 core is used in sum.

                                                                               

                                                                               

                                                                              While not something I would do every day, browsing in 1:1 in the Library makes a great deal of sense when fine-tuning the auto-focus of a lens/camera combination.  In any event I find it  convenient to do this when culling images.

                                                                               

                                                                              And I have yet to see more than a single core active at a given time when traversing existing 1:1 previews at 1:1 in the Library module.  Yes, I realize I've said this same thing several time in recent history.

                                                                              • 36. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                                dpick2 Community Member

                                                                                Render on import..thanks, Rob, another one I didn't know about.  I found it and will use it from here on out.  Also, I see your point that editing an image will require another 1:1 render.  Thank you.

                                                                                Rob Cole wrote:

                                                                                 

                                                                                In case you don't already know, you can have 1:1 previews rendered upon import too.

                                                                                 

                                                                                And, you don't have to wait for it to finish, before you can start taking advantage of it - as soon as the first one renders, you can zoom it quickly to 1:1, while the next is being rendered...

                                                                                 

                                                                                 

                                                                                dpick2 wrote:

                                                                                 

                                                                                However, I have had issues with looking at images where I have already viewed in 1:1 and come back at a later point and still had to wait while a the image was rendered.

                                                                                 

                                                                                If you change settings via quick-develop, or develop module, 1:1 lib preview will need to be re-rendered next time you visit in lib (this assumes Lr functioning normally. If there is a bug, it may decide to re-render again needlessly).

                                                                                 

                                                                                I think there is room for improvement assuring lib previews are up2date. For example, lib preview could be marked for update when changes are made that will cause a re-loading. And then, photos so marked could be updated in the background.

                                                                                • 37. Re: LR4.1--Is there a way to speed up 1:1 "zoom?"
                                                                                  bob frost Community Member

                                                                                  From: "Bob_Peters

                                                                                  Wow! That's impressive.  I wish I had that much "horsepower"!

                                                                                   

                                                                                  Well, apart from the obvious reply - buy a PC! - I wonder whether the Mac

                                                                                  version of LR has a problem with twin processor Macs. There seem to be

                                                                                  several people with twin Xeon Macs having similar problems, and although I

                                                                                  know nothing about how a program schedules stuff to be sent to twin

                                                                                  processors, I just wonder if that is where your problem lies. Your comments

                                                                                  about only one core being used most of the time would support that idea.

                                                                                   

                                                                                  It's not just 'horsepower', because my twin-core Samsung laptop (with SSD)

                                                                                  is the same - not quite as fast a response as my desktop, but some of that

                                                                                  may be screen-response differences. It still changes in less than half a

                                                                                  second - no loading or waiting.

                                                                                   

                                                                                  Bob Frost