10 Replies Latest reply on Aug 6, 2012 5:34 PM by OrlandoJetset

    CS5.5 scratch disk needs?


      A friend is going to build me a new PC (4 to 8 gigs of RAM) and install CS5.5. on Win 7 Ultimate.


      I know nothing about SCRATCH DISKS or even how to set that up but  I have the choice of either a single 1TB hdd or two 500GB hdds (or two 320GBs) but don't know what the best set up is for CS5.5 to allocate "scrath disk" space.


      He said he could "partition" the 1TB drive or install two drives. He's not a Photoshop user (he's an engineer who's built a lot of killer PC's as a hobby for friends) and said to ask some experts what the best case scenario would be for the scratch disk set up.


      I'll be working on large art files and camera RAW files so any help/advice on how to set up this "scratch disk" thing would be enormously appreciated for the technically challenged like me!


      Thanks so much in advance for any assistance!

        • 1. Re: CS5.5 scratch disk needs?
          Noel Carboni Level 8

          Don't partition the drive - that helps nothing.


          The basic idea is to try to get multiple drives working at the same time, to improve performance.  The old, sage advice is to put a separate drive in the system for Photoshop's use, separate from the OS drive, so that Photoshop can be swapping to/from its file while the OS is doing its thing with its own swap file. 


          But an alternative could be to create a RAID 0 array with multiple drives making up a single volume.  That tends to help everything be faster.  If you have the budget for it, multiple SSD drives making up a RAID array can make for a hyper-fast system, and the fact that there is no seek time means there's essentially no downside to having the Photoshop scratch space and system on teh same volume.  I have four OCZ SSDs in the array that makes up my drive C: myself, and I wait for nothing.


          If you do go with SSDs - which of course are more expensive than spinning drives - don't skimp on the space, or you'll end up wasting a bunch of time later when you're constantly fighting disk-full situations.



          • 2. Re: CS5.5 scratch disk needs?
            Level 5

            The optimal performance is obtained when the primary scratch disk is on a physically separate internal hard drive, separate from your boot or "C:" drive.  A partition volume of the boot drive does NOT help at all, as the Photoshop scratch disk would still be competing with the swap file of the OS for the use of the single set of read/write heads.


            Depending on your workflow, numbers of history states, etc., figure on 50 to 70 times, or more, the size of your largest file multiplied by the number of files you have open at any given time.


            I keep a dedicated 250 GB internal hard drive as my primary scratch disk, other users have more.

            • 3. Re: CS5.5 scratch disk needs?
              Level 5

              As you can see, I type a lot slower than Noel. 

              • 4. Re: CS5.5 scratch disk needs?
                PSBoston Level 1

                Wow, I'm confused by Noel's highly technical reply! Hey Noel, I'm an artist (painter) not a techie (thanks for your reply, though)!  I can count the hairs on a triple zero sable brush, but am clueless about computer innards. I am on a serious limited budget and this friend is doing me a huge favor by building a quad core for me in exchange for something I own.


                1. Okay, so forget about the partition on one drive right? (I've been running PS 7.0 on a single 80GB hdd for 6 years with no scratch disk, which shows how lucky or just plain stupid I am).


                2. Forget about RAID and whatever those SSD things are mentioned, I can't afford that.


                3. So TWO separate hard drives should be installed, one with Windows 7 on it (anything else on it?) and the second driver for my personal files, photos, all other programs including CS5 and as the scratch disk for CS5?

                If that's the correct set up, what should he do when installing CS5 (should the program itself also go on the second drive? And do we need to do something in the CS5 interface to allocate the second drive as the scratch disk?


                Thanks for helping me!

                • 5. Re: CS5.5 scratch disk needs?
                  the_wine_snob Level 9

                  I agree with Noel and Station_Two.


                  Depending on the data transfer speed of the disks that you mention, I would go with the 1TB. While PS, as of ~ CS, can use up to four separate disks for Scratch Disk, one does not have to do so.


                  I go with a minimum of three physical HDD's (like has been said - NO PARTITIONS), but then I edit a lot of video, and following along the guidelines above, separate the I/O (Input/Output, or HDD's), to keep them from being called upon to read/write at the same time. I locate my media files on the third disk. With PS, that really does not make any difference, as even large Still Images are smaller than most video, plus the entire Image file is written into memory (RAM and probably Scratch Disk) anyway.


                  As a bit of background, the Scratch Disk is "virtual memory," and is used when one does not have enough RAM - with large images and many operations, they will not, so Scratch Disks come into play. Keeping them separate from the OS, the program, and ideally the Windows Virtual Memory (Page File, or basically Windows' Scratch Disk) will greatly speed things up, as there are no I/O bottlenecks.


                  Hope that helps explain the reasoining with Scratch Disks and their location.


                  If not, do not hesitate to ask again, or ask for clarification that any of us have said. We'll be glad to restate in a different way, to help.


                  Good luck,



                  • 6. Re: CS5.5 scratch disk needs?
                    PSBoston Level 1

                    To Bill Hunt:
                    I won't be doing any video and won't be using most of the other things in the Master Collection either like InDesign, etc., because they're totally useless to my needs. All I do is manipulate/edit my own photos and artwork, period, but these files can be large by the time I'm done with them.


                    So I assume that having just one hard drive, the 1TB, is fine?  I'll have a minimum of 4GB DDR3 and might opt for 8.

                    Will that extra RAM be worth the price for better performance or not?


                    The OS will be Windows 7 Ultimate 64 bit.

                    Thanks so much again, I so appreciate everyone's help and advice. Great Forum!

                    • 7. Re: CS5.5 scratch disk needs?
                      Curt Y Level 7

                      I personally like 2 and preferably 3 internal hard drives.  I prefer to have my programs on drive c:, my files on another and a scratch disk on 3rd.  The file disk should be the largest of the 3.


                      You should also have a seperate physical drive for backup.  This could be on the 3rd drive, or an external.  Hard drive fail and it is important to have frequent backups on some sort of a scheduled basis.



                      The other critical item is the video card.  You do not need a high end one, but it should also not be an Intel on board one.  ATI and Nvidia are the big players.

                      • 8. Re: CS5.5 scratch disk needs?
                        Noel Carboni Level 8

                        Go with two physical hard drives and 8 GB RAM.  Every penny you save now will cost you time and frustration later.



                        • 9. Re: CS5.5 scratch disk needs?
                          the_wine_snob Level 9

                          I agree with Curt here. A second physical HDD, will benefit you, as it will split the I/O load over two HDD's.


                          The third could be used for you Image assets, but is more of a benefit with video.


                          Good luck,



                          • 10. Re: CS5.5 scratch disk needs?

                            I'm thinking of getting a 2TB Caviar Black as 3rd drive to use for "Adobe Scratch, Cache, Previews, and Exports".  I will however partition it because I will also use this drive for Virtual Instrument (VST) samples and cannot at the time afford an additional drive just for that. Plus I have no idea how much the Adobe scratch and cache needs...


                            I think what I understood from this discussion is that the adobe cache can be on a partition of a secondary drive, as long as its not on the same drive as where the OS or Adobe program installations are.