5 Replies Latest reply on May 10, 2011 9:51 AM by StencilMedia

    Memory allocation in CS5.5

    StencilMedia

      Hello!

       

      I've just got After Effects CS5.5 and I've got a questions about memory usage that I can't seem to find the answer to. If anybody could help out I'd be very grateful.

       

      Ok, so I'm on a quad core laptop with 8Gb of RAM. My total RAM available for After Effects is 6.2Gb. In the memory and multiprocessing window, I have the following options when it comes to 'RAM allocation per background CPU' and this is how many cores it says will be used if I make that selection:

       

      0.75  4 cores

      1.00  4 cores

      1.50  2 cores

      2.00  0 cores

      3.00  0 cores

       

      So here's the questions; surely I should be able to set it to 3.0Gb and still be able to use 2 cores... or 2.0Gb and use 3 cores? And shouldn't 1.5Gb allow me to use all four? I just want to clarify really, if I do set it to 0.75Gb and using 4 cores, will it actually only be using 3.00Gb of RAM or does some magic happen behind the scenes? 

       

      Thanks!

        • 1. Re: Memory allocation in CS5.5
          Todd_Kopriva Level 8

          See this page. Read what it points to.

          • 2. Re: Memory allocation in CS5.5
            Dave LaRonde Level 6

            StencilMedia wrote:

            I'm on a quad core laptop with 8Gb of RAM. My total RAM available for After Effects is 6.2Gb.

             

            8 gigs may sound like a lot, but it isn't really a boatload of memory for AE. 

             

            At work I have a dual quad-core machine with 8 gigs, and I don't even think about using multiprocessing; I find that it's just not enough to use multiprocessing very effectively.  At home I have a dual quad-core machine with 24 gigs, and multiprocessing works nicely.

            • 3. Re: Memory allocation in CS5.5
              StencilMedia Level 1

              You get around Dave, just read a reply of yours for some issue a guy was having on Creative Cow!! Wouldn't you consider using 2 of your cores with around 2.5Gb to 3.0Gb on your work setup though? Surely that's sufficient for reasonable performance when it comes to multiprocessing... as long as you're not working on 4K projects or very complex 1080 ones.

               

              I know 8Gb isn't anything to shout about these days but I needed a windows laptop rather than a desktop and the only one I could seem to find that would let me put 16Gb in it was twice the price... to steep for me at the moment, but might treat myself for Christmas.

               

              The main thing I was curious about though was not why I shouldn't, but more why I couldn't (from the looks of it), use more than 1.5Gb per core... seemed strange to me.

               

              Thanks!

              • 4. Re: Memory allocation in CS5.5
                Todd_Kopriva Level 8

                > The main thing I was curious about though was not why I shouldn't, but more why I couldn't (from the looks of it), use more than 1.5Gb per core... seemed strange to me.

                 

                Did you read what I pointed you to? Please do so.

                 

                I'll explain the arithmetic for the simple example that you gave:

                 

                Let's say you allocate 1.5GB per process. You've got 2GB reseved for other applications, leaving 6GB for After Effects. The foreground process takes 1.2x1.5GB=1.8GB, because it needs some extra memory for things like the UI. That leaves 4.2GB. At 1.5GB per process, that's enough for two background processes to start.

                 

                In the 2GB case, you've got 3.6GB left over after the foreground process takes its share, and 3.6GB is only enough to start one background process at 2GB each. There's no point in starting one background renderer, so it doesn't bother.

                 

                This is explained in the materials that I pointed you to earlier.

                • 5. Re: Memory allocation in CS5.5
                  StencilMedia Level 1

                  Thanks for that Todd. Yeah, I read all five articles (skipped the purely CS4 ones), but didn't see anything relating to the foreground using 1.2 times your background usage. I didn't follow all the 54 links within those articles though, so it's possible it was in one of those!

                   

                  Thanks for the answer.