9 Replies Latest reply on Nov 24, 2011 10:24 PM by Ted Smith

    Can someone explain how .prel files work?


      Can someone explain how .prel files work?  My C drive is O/S and programs, my D drive is storage and the project file(s) (the .prel file) are on my E drive. 

      How is this supposed to be more efficient/faster?  P.E. (C drive) has to constantly communicate back and forth across drives with the .prel file and all the files in the subfolders?  It seems like it would be slower. 

      As I mentioned in a previous post; my zooms in/out of the Timeline are VERY slow.  It is almost 1 second before the Timeline gets bigger/smaller.  Any info would be great,thanks!








      Windows 7 64 bit, i7 980x @333 6 core processor, 12 GB ram DDR 1600, Radeon 5850 GPU PE 9

        • 1. Re: Can someone explain how .prel files work?
          nealeh Level 5

          It is faster provided that your C,D, and E drives are PHYSICAL drives. This is because the drive controllers can operate simultaneously.


          If you only have one physical drive and you have partitioned it into C, D, and E then performance will suffer as the drive head is constantly shuffling between different partitions on the same disk.


          Insanity is hereditary, you get it from your children

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          • 2. Re: Can someone explain how .prel files work?
            Ted Smith Level 3

            If you use the slider to change timeline size it should be instant although I noticed this was slow when I once added a mp3 audio track so you may have a problem with your camera video encoding? What camera and settings are you using?


            To edit faster, select the timeline option that only shows a pic at the start and end of each clip.

            I sometimes temporarily switch off thumbnail pics completely (control on left of timeline) when I want to mainpulate finely a clip say to music and use the space bar to stop and start the preview or drag the pointer and watch the preview. Thumbnail pics are only useful to identify seperate clips, not to see what is in one clip unless that clip is very long.


            Defrag your drives regularly, particularly just before you add video files or start a new project.


            A one second delay stating preview  is not bad if you have a lot of effects like transitions or sharpening added to clips.


            As I understand it the project files contain the instructions as to what part of the video files to use to assemble the timeline, the thumbnails on the timeline etc. Any rendered versions of edited clips should also be on the project disk.


            It is easier for the computer to read and write seperately to another disk than to new contiunually reading video and jumping to a different area of the disk to read and write instructions at the same time.


            Some disks write slower than they read and not all are the same so make sure you have a fast writing disk for your project disk (Sata3)

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            • 3. Re: Can someone explain how .prel files work?
              the_wine_snob Level 9

              By using multiple HDD's, one is spreading the I/O (Input/Output) load over various HDD's. The controller is faster than a single HDD, being tasked to read/write from/to multiple places. One of the first laws of physics is that an object cannot be in more than one place, at the same time. The heads on a HDD are no different. If requests for multiple reads are made, the heads will position themselves over on place on the platters, read, and then move to the next requested location, and so on. However, with multiple HDD's, and a good, fast controller, the heads of each HDD will be placed, where necessary, so reads are done at once, from multiple locations.


              For ultimate performance, a good setup would be as follows:


              C:\ system OS and programs (more reading being done here, than writing)

              D:\ Project files (PREL's in this case)

              E:\ RAID 0 Scratch Disks for Media Cache, but not Render files (both reading and writing)

              F:\ RAID 0 Media files (more reading, but also writing)

              G:\ RAID 0 Export/Share and Render files


              Some go so far as to separate out Audio Assets from Video Assets, and use a separate RAID 0 for each


              The downside of that "ultimate performance" setup, is that when a Project is completed, to clean up, one has to go to many HDD's, and locations. There can also be issues when Archiving a Project, because things are scattered about.


              I get "good performance" by having my Project, Copies of my Assets and all Scratch Disks on one HDD. What I give up in performance, I make up for with housekeeping chores, when the Project is done. I still spread my OS/programs from my Projects, with separate physical HDD's.


              Good luck, and hope that this helps,




              PS - Above, I mention RAID 0, but even greater speed can be achieved via many HDD's in the Array, and perhaps a RAID 50. RAID 0 is just two physical HDD's. Also, for RAID, I recommend a dedicated RAID controller card, and NOT software, or the MoBo's RAID capability.

              • 4. Re: Can someone explain how .prel files work?
                Elwoodbluesman Level 1

                Thank you to all of you for your responses!  Good physics analogy Bill!   Bill,  is it okay that my media cache, rendered files are on the same disk as the .prel file(s)?  That is how PE has them arranged/configured (under/in the .prel folder) when you set the location for the .prel file.  Does it make much difference?

                • 5. Re: Can someone explain how .prel files work?
                  the_wine_snob Level 9

                  This is how my Projects are most often setup. First, that allows me to clean things up efficiently, and second, I often migrate my Projects between computers, so I want everything on one of my FW-800 externals. As mentioned above, I do give up some performance, in that scheme, but I have never experienced any lags, even with FW-800 externals. For me, eSATA externals would be faster, and when one is talking SATA internals, the performance hit will be minimal, in my limted benchmarking. I doubt that a user would even be aware of the performance gain, unless they had two, otherwise identical computer, side by side.


                  Now, one thing that will very likely be noticed, would be to Export/Share to an equally fast HDD, that is not doing any other duty on the Project. Still, with my externals, I Export to a set of folders in the Project's hierarchy, because I am most likely to then take things into Encore, and might also be using that external between computers. A bonus to me, with that layout, is that when the DVD's are finsished and delivered, I can easily Archive the Project (everything necessary is in one location), and then with one Delete, clean it all up.


                  This ARTICLE gives an outline of my Projects' folder structure. Remember, I acknowledge a slight performance hit, with this scheme.


                  For an overview on the PREL files, and what they contain, plus some tips on Saving, this ARTICLE might be useful.


                  Good luck,



                  • 6. Re: Can someone explain how .prel files work?
                    Ted Smith Level 3

                    I have my doubts about RAID, I suspect it was invented in the days when disks were far slower than they are today and didnt have their own internal caches.


                    My computer was originally set up with only 2 disks in RAID so it looked like 1 disk.

                    When I bought PE9 it was very slow so I added another disk for video files only.


                    I then disconneced the RAID and made the original disks 2 independent disks, this made my computer now with 3 independent disks.


                    I put only the project file on the 'new' freed up disk


                    It made PE9 go much faster.

                    • 7. Re: Can someone explain how .prel files work?
                      the_wine_snob Level 9



                      For certain operatons, RAID is still a great setup, such as HD media files, Export/Share, Render files, etc..


                      There are also three types of RAID. This is for the 0 Levels:


                      • Software managed - not much real difference in speed vs two single discs.
                      • MoBo hardware managed - usually faster, but as the MoBo is involved, can have I/O bottlenecks.
                      • Dedicated hardware managed - this is where the real speed increase comes, and especially if one adds a few GB of RAM to the controller card.


                      The performance of any RAID will depend on how it's managed. The performance increase can be minimal, to dramatic.


                      As you observed, 3x separate, physical HDD's will usually show an increase in performance over a single RAID Array, even if it's managed by a controller, when editing video.



                      • 8. Re: Can someone explain how .prel files work?
                        Ted Smith Level 3

                        I recently purchased a Sata3 disk

                        Along with it came a leaflet on how to increase oild disk to

                        • 9. Re: Can someone explain how .prel files work?
                          Ted Smith Level 3

                          I hit a wrong combination of keys!

                          I recently purchased a Sata3 disk

                          Along with it came a leaflet on how to increase old disk speeds to Sata3 using software included on the CD that came with the new one


                          It involved installing a small solid state disk and running in a sort of RAID configuration so the old disk and the solid state appeared as one disk, the solid dtate acting as a large cache, the data being written to the hard disk slightly later.

                          This would OK for recent data manipulation such as rendering and reading consequtive files in bursts like previewing but would not be any faster for large blocks of new reading siuch as file copying


                          Unfortunately it is probably now cheaper to buy a new Sata3 hard disk!


                          Also many new motherboards only have 2 x Sata3 socketsm trhe rest being Sata2.