Found a significant LR4 speedup - regenerate ACR cache

Just check that the old preview cache isn't orphaned on the old drive and taking up space.

I just found the 'Like' button. Good man/woman/person.

For future reference, generating 1:1 previews (e.g. via library menu selection) also generates develop cache entries.

I have significant problems with near lock up in LR4 and have posted a discussion (it takes HOURS to import a couple hundred photos, minutes to load a photo just to view sometimes).  There have been no suggestions in reply to my original post -so maybe I can tag along here for some assistance?  Please? In LR, I opened the preferences (in Edit) and found that my Camera Raw Cache Settings were set at 1. GB maximum size, with the Video Cache set at 3.0 GB.  Hate to be dense, but I want to be sure I am not causing with more problems.....so, I should purge cache on each first, then change maximum size to 100? Since mine is set on 1. that seems pretty drastic, since my system says it has 308 GB free out of 465. 

I have an HP server which I can can use (instead of the default C drive which it is set to). My system is less than 2 years old,  Windows 7- my processor is AMD Phenon(tm)  II x 4 925 Processor.  My hard drive back up has plenty of space -  4 terabytes.  Could Purge Cache and change these settings in any way cause another problem?  Should I change this to my hard drive -if so, would I use the same file location, except change to my server? 

I have a Mac with the same cache settings, and it is lightening fast with LR3 compared to this.  I really don't know how to ask the right questions -my knowlege about computer systems, etc. is limited.

Rosalynsam,

The 1 Gb seems very low. I just checked my cache folder and it is actively using around 3 Gb and has not done extensive work since a last purge a few days ago. 100 Gb may be more than you need but I think suggestions to allot at least 20 Gb are common. Mine is set for 35 Gb but is probably more than needed. I believe that the Video cache is just for displaying video files in LR and has no effect on still photos.

I would not think putting your cache on a network server a good idea. Network connections are not fast compared to drive writes. You would want it on a fast local drive for best performance. If you have more than one drive you may want to see if separating the catalog and the photos helps out your performance at all.

Another thing to try would be to totally delete your Previews and see if letting them rebuild from scratch helps out at all.

SistersCountry wrote:

 

Rosalynsam,

 

The 1 Gb seems very low.

50 gb here...

Adobe recommends ACR cache of "10gb or more" for Lightroom

http://helpx.adobe.com/lightroom/kb/optimize-performance-lightroom.html

I think the norm for the ACR cache is around 50GB just to make sure it's big enough for a large shoot.

That would be one heck of a shoot - about 140,000 images! (with the cache per image for a 21mp capture averaging 350k)

I was simply passing along what Adobe - the author of the software - recommends.

I figure that 2x the max amount of images you ever import at a time is probably a good safe minimum to work on that particular shoot.  So, since I sometimes come near to filling up two 16GB cards in a big sports shoot, a safe min for me would be 2x16 x 2 = 64GB.  I set mine to 100GB.

The cache is not the same size as the capture. It's about 2 or 3% of the size (e.g. 97% smaller). Your 100gb is enough for almost 350,000 photos.

I would think your ACR cache be 3 to 4 times larger than the total size of all the RAW images you want to work with at a time.  I am saying that because the ACR cache contains the 3-colors-per-pixel versions of your 1-color-per-pixel RAW images and depending on if the data is compressed much if at all, it could be much larger than the RAW size of the corresponding image.  If you normally barely fill up a 2GB card with your RAWs, then a 5-8GB cache might be ok.  If you fill up a 32-GB card, then a 100-150GB cache would be ok.

I would think your ACR cache be 3 to 4 times larger than the total size of all the RAW images you want to work with at a time.  I am saying that because the ACR cache contains the 3-colors-per-pixel versions of your 1-color-per-pixel RAW images and depending on if the data is compressed much if at all, it could be much larger than the RAW size of the corresponding image.

The cache is 97% smaller than the capture, not 3 to 4 times larger. Average cache size is 350kb. Just look on your HDD.

If you fill up a 32-GB card, then a 100-150GB cache would be ok.

If you fill up a 32gb card you need about 400mb for the acr cache in LR

In my experience, when Lightroom is operating normally, ACR cache hits generally have only a very minor effect on performance. If it has a big effect, I think you've got some wonky cachin' goin' on, like jfriendl0 had...

Interesting - I just checked my cache - old entries are very big - new entries are very small. How about that?

Perhaps there were some significant changes in what the cache does in Lr4???

Hi Rob,

Since I use DNG with fast load data embedded the ACR cache seems to be used much less.

That is a new LR4-feature.

Cornelia

Hi Cornelia,

Right - I had forgotten about that. I wish they would have allowed non-DNG users to take advantage of that technology too, but since I don't use DNG, I wonder what the deal is in my case.

Rob

Something has definitely changed or is screwed up now.

Like you, my cache entries used to run about 5MB for 13MB D300 file. Now they are in the 400K range - whoa, that's quite a difference!

Haven't done any benchmarks since noticing this difference.

And my largest is only 3.9 with an overwhelming majority closer to 500k. 12mp .arw raw files. All over the map from 99k to 999k for 95% of them.

I have cache going way back and the max is 3.9mb, with the average being 350k. In any case it is somehting like 75-95% smaller than the file, not 3 to 4 times bigger.

13 sounds big. 500k sounds about right for a standard preview. Have you been doing a lot of 1:1 preview recently? They should be bigger.

I'm moving to a DNG workflow for the Fast Load Data. Older non selects will go to Lossy DNG. They're already backed up as Raw and right now, I've probably mere thousands of shots I'd be lost without.

Pre Lr4, all cache entries were exactly the same size (and big), given the same preview settings (I can't remember if it was quality or resolution that affected it, but it was not what one might think), and the same model camera. Now, the sizes are image dependent, and small. Something has definitely changed, ACR-cache-wise, a lot, in my copy/system. Not using DNG.

I was used to seeing cache entries in the 17mb range for my circa 25mb raw files. However a few days ago I purged my ACR cache, deleted my preview cache, then rebuilt 1:1 previews. Checking on the cache this evening I was surprised to find average cache entry size well below 1mb, probably about 400k. Just ran a quick test:

Copied 9 raw files, all more or less identical night shots (around 25mb each, hardly any variation) to my desktop. Then imported 3 each into LR2, LR3, and LR4, then checked the cache.

For the 3 LR2 imports, the cache entry was 17,404kb for each one, no variation

For the 3 LR3 imports, the cache entries were 497kb, 942kb, 942kb

For the 3 LR4 imports, the cache entries were 1218kb, 932kb, 327kb

Go figure. I have no idea of the significance of the huge difference between LR2 versus LR3&4.

Somebody needs to do some benchmarking!

Just had a look. I've a mix of 500k and 8.8Mb files recently.

All small for me since purging recently (minutes ago) - regardless of process version.

Purged.. some of them were well old and despite the 50 gig limit I entered, it was 56Gb..

I purged the cache and increased it to 50GB - no significant improvement - if I try to scroll through the catalog, I may get a few that load quickly, (or not), then it will bog down, and take over a minute just to preview (load).  Develop seems to work okay once I get to it. I don't even dare to try to load or export, because that was even worse previously - either locked up or exceedingly slow. 

I am on a severe time crunch, so at this point, LR4 is unusable, so I want to revert back to 3.6 - how do I do that?  I fear just removing LR4 from my system will cause more problems....any idea about that?  I am so incredibly frustrated with Adobe,  with the only support from Adobe requires me to pay to fix what I believe to be is their problem, unless I am missing something.  I do appreciate the replies as to how to try to fix this.

Thanks in advance

I would definitely try to get to some ground zero, then work back up if possible, which means:

New catalog

import one new photo - same problem? import a half dozen more - problem now?

If it works when you have a freshly created catalog, catalog was the culprit.

Else:

Reboot machine

Reinstall Lightroom

Reboot machine

Try again... try other things...

R

To know whether this cache change improved things, I would recommend purging the cache, then do some operation to an entire directory of images (I chose to change sharpening by one unit) and then tell it to regenerate previews.  This will cause it to access every image in the directory and will rebuild the cache for that directory... If you don't cause it to rebuild the cache by doing some operation that causes it to recache everything, then it will be hard to know whether things are slow just because it has to recache every RAW file on each access or because you have some other issue.

Render 1:1 previews. It does the cache also

Man....I'm confused. I'm on a Mac, OSX 10.6.8 and always shoot and convert RAW CR2 files to DNG (Canon 5Dmk2) when importing to LR. I set my ACR cache to 35.0 GB and also purged it.

I edited a bunch of photos and synchronized them, just to make sure I had some changes. I generated some standard previews and also half a dozen 1:1 previews. My cache is totally empty....as in "NADA". There is not a single file there. I double checked to make sure I had the right folder and drive. Could the files be hidden or invisible? Could it be that I am shooting DNG files?

Even on the 1:1 previews, there is a delay when showing the image at 100% magnification. Going from one image to the next initially shows the image sharply, but just for a split second, and then it defocuses as if there was no cached preview at all. After 2-3 seconds, it comes back into sharpness. This is a brand new catalog (I decided to start from scratch, since the original transfer was a total dog).

Does this sound right??

Thx,

Lou

I've been complaining about this for years - it's how Lightroom has always worked.

The develop module shows you, if not cached in ram, but cached on disk (ACR):

1. The present Library preview: good.

2. An initial develop view based on the cache: bad.

3. A final develop view: best.

If I had my way, it would just skip phase 2 altogether, unless there is no library preview avaliable.

Better still, invent a disk caching scheme that does more good - ACR caching makes for only very minimal performance improvement, at best < 15%.

Note: if cached in ram, then it's lightening fast.

Rob

Lou,

I experienced something similar. Nothing appeared in the cache folder.

Try hitting the "Choose" button in your preferences and then choosing the folder that you want your cache kept in. I did that and that folder started filling up as I brought various raw files up in the Develop Module.

Hal

Try hitting the "Choose" button in your preferences and then choosing the folder that you want your cache kept in. I did that and that folder started filling up as I brought various raw files up in the Develop Module.

Hal, thanks for the comment.

I did select "Choose" before I posted and again after reading your message (just to be sure), but nothing at all is being written to my cache folder, even after editing images. These are all DNG files.

Are you on a Mac or PC?

Lou,

PC, and I did it with NEF files. If you have DNG and created them with fast load data, I think the ACR cache won't be used.

Hal

Lou,

I'd be very interested in the results if you benchmark improvements resulting from fast-load data.

Rob

Just a reminder that the ACR cache is used in a few places, mostly for read only. All you have to do is scroll through grid mode in the Library against some photos you haven't looked at in awhile, and you will see new entries. If you are like me and have a 4x4 grid in the library as a default, you will see 16 new cache files. You will know it is doing this if the grid previews are greyed-out at first.