11 Replies Latest reply: Jun 25, 2014 4:00 PM by Noel Carboni RSS

    scratch disks and RAM usage

    curiouscat951 Community Member

      i would like to understand the relationship between scratch disks and RAM usage in Photoshop.

       

      While i was working on a fairly big psb file (2gb), photoshop kept prompting that I was out of memory, but in fact the utilization was only 75% (i had 16gbs total, photoshop was only using 7gb, and i allowed PS to use up to 14gb in total). when it says out of memory, it was actually my scratch disk at fault ( i only set 1 scratch disk, which was my 120gb SSD running out of space).

       

      any idea how I can optimize PS to use up all my RAM first before even touching my scratch disk? (short of using a RAMdisk, please).

       

      thanks!

        • 1. Re: scratch disks and RAM usage
          JJMack Community Member

          Photoshop manages resources it allocates from your OS and does not return them till it is closed down.  I have 40GB of ram on my workstation.  I do not remember Photoshop ever using more then 16GB of RAM but I have seen it use in excess of 120GB of scratch space. Photoshop also seem the fill up the first scratch disk before allocating space on the second scratch disk.

          • 2. Re: scratch disks and RAM usage
            KJezza Community Member

            Good point JJ, I should now assign my secondary scratch (spare drive) to be my primary so PS doesn't fill up my primary (HD with the OS on it) first.

            • 3. Re: scratch disks and RAM usage
              JJMack Community Member

              If I look at by system before starting Photoshop I'll see 0% CPU utilization an 5.15GB of RAM allocated in use. After I start Photoshop and open nothing I see 5.72GB so Photoshop is using .56GB of RAM Task Manager shows Photoshop working set to be 499,616KB around 500MB. I see several file in my user ID temp space I believe Photoshop wrote. One Large one named "Photoshop Temp68610873900" size on disk 3.68 GB (3,958,374,400 bytes).  No document is even opened in Photoshop. CPU 0%

              • 4. Re: scratch disks and RAM usage
                curiouscat951 Community Member

                my question is, why would PS be using the scratch disk when there's plenty of RAM available at its disposal? RAM is many times faster than my SSD.

                • 5. Re: scratch disks and RAM usage
                  JJMack Community Member

                  Only Adobe can answer that try using their site Photoshop Family Customer Community

                  • 6. Re: scratch disks and RAM usage
                    Semaphoric Community Member

                    The scratch disk is Photoshop's main memory; RAM is used as a cache. Always been that way. Should it be changed, now that many systems have tens of GBs of memory? Maybe Chris Cox will chime. in.

                    • 7. Re: scratch disks and RAM usage
                      KJezza Community Member

                      It is an interesting question: why not fill up the fastest memory (RAM) before using read-write or page swapping memory?
                      My guess is that the massive amounts of memory Photoshop has historically used and now currently uses has surpassed the average amount of RAM in the average users machine.

                      That said, use up all of the RAM (which you can now allocate) and your OS suffers. Even though you can tell it the amount in Prefs/Performance...?

                      • 8. Re: scratch disks and RAM usage
                        JJMack Community Member

                        At this stage 20+ years of Photoshop development it would be a major undertaking to change Photoshop basic mode of operation I would venture to guess.

                        • 9. Re: scratch disks and RAM usage
                          KJezza Community Member

                          I agree JJ, but now that memory is so cheap (especially RAM) why would Adobe not optimise to RAM? Perhaps it's OS based but I can't  understand otherwise…

                          • 10. Re: scratch disks and RAM usage
                            mapyron@att.net Community Member

                            I am curious about this also. I just reinstalled W-7--have 11 G of physical memory--a ton of hard drive empty space also, and I have been wondering why PS_CC is so slow--since basically I have only put my Security and Browser in addition to Adobe back on the Dell XPS computer..... At least now it does show the downloading percentage (like .psd file) , but that must be what is happening.  I do think that some of these "frozen" screens I have been experiencing, was because the program was using scratch disk, instead of the Ram... I came up from CS-5, and can't describe it in detail, but just realize how slow PS-CC is in most everything.  Going back and see if reallocating will help...

                            • 11. Re: scratch disks and RAM usage
                              Noel Carboni Community Member

                              Photoshop will use all the RAM you allow it to.  Mine's set to 96% (of 48GB).  I've seen it use 44GB.

                               

                              It creates scratch files and moves old history data out before the crunch hits, while you're working so that if you do run short of RAM it will already have more that it can immediately use.  It's very sophisticated.  They left simplistic implementation behind about 2 decades ago.

                               

                              -Noel