14 Replies Latest reply on Oct 19, 2011 1:01 AM by Harm Millaard

    Choppy video despite low system usage


      Hi all, I upgraded my system yesterday to:


      AMD 1055T 6 core CPU

      16Gb DDR3 1333 RAM

      using my existing Nvidia GTX295 896Mbx2

      I have a separate disk for projects and scratch, both 7200rpm


      My issue is, when I preview a clip encoded with divx, it plays smoothly for about 1-2 minutes. In software mode, CPU usage never exceeds 25% and with MPE enabled, GPU usage never exceeds 10%. After 1-2 mins, the video becomes extremely choppy and even stalls, despite audio continuing. The problem is present in both software and MPE enabled.


      If you pause the preview and wait 10 seconds, this will enable another 5 seconds of smooth video before the choppiness sets back in. I am baffled by this, as system resources seem untaxed. I am unsure how to measure whether my hard disks are the bottleneck.


      Can anyone please help me resolve this? I built this system for my wife, who is very excited to learn Premiere Pro. I understand I should have bought an Intel I7, but my budget unfortunately did not cater for this.


      Thank you,



        • 1. Re: Choppy video despite low system usage
          RjL190365 Level 5



          Part of the problem is that you are not using the GTX 295 to its fullest in CS5 (because Premiere Pro wouldn't let you do that no matter what you tried). Premiere Pro supports only one GPU for GPU acceleration. Unfortunately, the GTX 295 is actually a dual-GPU part in which each of the GPUs is only about as fast as a GTX 275. What happens here is that only half of the GTX 295 (this means one of the two GPUs) gets used at all by CS5, leaving the other GPU completely wasted. So, you got ripped off with the GTX 295 or any other dual-GPU part since no version of Premiere Pro to date supports more than one single GPU (or in this case, half of a dual-GPU component). And due to the slower clock speeds, the GTX 295 performs barely any better than a GTX 260. This is one clear example that the most expensive GeForce of its generation is actually slower than some of the less-expensive members of the same family. (The same situation is repeated in the GTX 590, which according to the one result in the PPBM5 results list that performs nearly 10 times slower than the average GTX 570 in exports and renders from the timeline even in MPE's GPU accelerated mode).


          And this is also the reason why Adobe advises against the use of dual-GPU SLI configurations such as the GTX 295 or GTX 590 (or two identical single-GPU cards in SLI): They are much slower in CS5.0.x than many of the much cheaper single-GPU solutions because there is far too much switching within the dual-GPU cards themselves (or the SLI bridge), adding a rather severe amount of latency.


          In addition, which version of Premiere Pro were you using? I saw three systems using GTX 295s on the list, and the two that ran CS5.5 were faster in the export/render test than the one that ran CS5.0.3. Only one of the GTX 295-equipped systems achieved a time of less than 20 seconds - such short times that are routinely achieved by mid- to high-end single-GPU cards - on the export/render portion of the PPBM5 benchmark (and that was an overclocked AMD Phenom II X6 system). The other CS5.5 result is held back by a slow CPU.


          In other words, you need to run CS5.5 just for that GTX 295 (or GTX 590) to even run as fast as most of the single-GPU cards. If you are running 5.0.3 or earlier, the MPE performance with such a dual-GPU SLI card will become slower than even the cheapest GeForce GPU.


          And that's not to mention that the AMD CPUs lack full support for SSE 4.x.

          • 2. Re: Choppy video despite low system usage
            adamjgan Level 1

            Thank you very much for your reply RJL. I had the GTX295 left over from my last system, which is the only reason I am using it now. Thanks for explaining its shortcomings, I wasn't aware that Premiere couldn't utilise the dual GPU. I am running Prem Pro CS5.5.


            I'm not convinced that the GPU is the reason for the choppiness, as I am running monitoring software for both my CPU and GPU and during a simple preview of an unedited video, CPU and GPU usage are both very low. They are hardly being taxed at all, yet the preview video stalls and gets very choppy.


            My wife isn't trying to do hugely complex editing, and this choppiness is spoiling the experience for her. Can you offer any advice on how I can improve this situation?

            • 3. Re: Choppy video despite low system usage
              Harm Millaard Level 7



              In addition to Randall's remarks there is another thing to consider, only two disks.


              You have three weaknesses in your system:


              1. The Phenom CPU, which lacks SSE 4.1+ support

              2. The GTX 295, which is only used at 50% of its capacity

              3. Only two disks.


              The combination of these three factors can easily lead to the choppiness you encounter. In addition, insufficient tuning may aggravate the problem. Did you check Adobe Forums: Guide for installing and tuning a Vista... which also applies to Win7.

              • 4. Re: Choppy video despite low system usage
                RjL190365 Level 5

                Thanks, Harm. I forgot about the disks. The OP could have had older-generation 7200 RPM disks that have lower sequential transfer speeds than any of the current-generation "Green" (sub-6000 RPM) disks. Worse, those old-gen 7200s were not (R)aid0'd (or worse, one of those is also being used as the OS drive), exacerbating the problems.

                1 person found this helpful
                • 5. Re: Choppy video despite low system usage
                  RjL190365 Level 5



                  Are you using a separate OS drive in addition to the two drives in your original post? Or is one of your two listed disks also being used as the OS drive?

                  1 person found this helpful
                  • 6. Re: Choppy video despite low system usage
                    adamjgan Level 1

                    Hi Harm and Randall,


                    Thank you very much for your insights into my problem. My current disk set up is:


                    160Gb SATA ?RPM Primary boot, Programs

                    500Gb SATA ?RPM Project Drive

                    320Gb SATA ?RPM Scratch Drive



                    As the CPU/GPU usage was measured as being low, I assume now that my HDD configuration is the bottleneck here. I've read some other posts and I see that the Samsung Spinpoint F3 1Gb drives are reccommended. I don't have the cash to do a RAID5/10.. I can purchase two of these drives. What would be the most optimal configuration, considering my current disks?


                    I will upgrade the GTX295 to maybe a 550Ti in the very near future also.


                    Thanks again,



                    • 7. Re: Choppy video despite low system usage
                      Harm Millaard Level 7



                      With three disks and not two as I understood earlier, I think that there is no pressing need to get one or more extra disks. Before spending money, I would tune the system first, meaning the uninstall of MSN, games, fax services, bluetooth and similar stuff not needed on an editing machine. Turning off UAC, maybe Aero, definitely the Sidebar, and setting a lot of unneeded services to either disabled or manual. Important, turn off compression and indexing on all disks. Well, just follow the suggestions in the tuning link I gave you earlier and see how much it improves responsiveness.

                      • 8. Re: Choppy video despite low system usage
                        adamjgan Level 1

                        Following the hard disk configuration guide you have posted Harm, although my hard drives are all 7200rpm - I ran the HDtune benchmark and found that I have some extremely slow drives!! I believe that this is the main problem with my Premiere Pro running so slowly. I will go for a 4x Spinpoint configuration, and I'll post results once I have done the upgrade hopefully in a few weeks.

                        Thank you Harm and RJL so much for your assistance. I was ready to throw in the towel before I came to these forums!


                        • 9. Re: Choppy video despite low system usage
                          RjL190365 Level 5



                          It's a good thing that you found the culprit: Hard drives with old-generation platter designs (with platters that store less than 250GB each) that can barely sustain half the sequential transfer speed as current-generation 7200 RPM hard drives (with 500GB or even 600GB platters). In fact, the culprit drives are slower in sequential transfers than even a "Green" 5400 RPM hard drive! (I confirmed this on an early 320GB Western Digital Caviar SE16 hard drive, which used three 107GB platters that had a maximum sequential physical transfer speed of only 65 MB/s on the outer tracks - less than half of what a 1TB Western Digital Caviar Black WD1002FAEX can achieve.)

                          • 10. Re: Choppy video despite low system usage
                            adamjgan Level 1

                            Dear Harm and RJL,


                            I wish to thank you for your input into my situation a few weeks ago. I have since replaced the old hard disks and am running the Samsung Spinpoint F1 1gb drives. I am still persisting with the AMD Phenom 1055 (2.8Ghz) CPU with 16Gb 1333 RAM. I ran the PPBM5, and scored 435, which places me around position 270, and in the top 10 of Phenom CPU's. Granted, its not the quickest Premiere beast out there - but it is sufficient for my needs. For a system which was built for well under $500 I am quite happy



                            • 11. Re: Choppy video despite low system usage
                              Harm Millaard Level 7



                              That is great news. But I don't see your results with a score of 435. Did you not submit the data or is there a typo somewhere (your side or my side)?


                              PM: Just received your submission form. I'll add those tomorrow.

                              • 12. Re: Choppy video despite low system usage
                                RjL190365 Level 5

                                For the total system price, Adam, you are in the same company with the AMD system as I am with the budget i3 system. In this comparison, both systems cost well under $500 (or just about $400 in the case of my i3 build). And though my score of 637 seconds was largely due to the system having only 4GB of system RAM, I felt that bumping the RAM up to 8GB would have helped significantly. In fact, of the 488 systems currently on the PPBM5 results list, my i3 system is one of only two systems with dual-core CPUs (not counting dual-processor systems) that ranked even in the Q1 range (the other, surprisingly, is an i5 laptop). All of the other systems with dual-core CPUs ranked in the D1 range, with most being near the bottom of the list.

                                • 13. Re: Choppy video despite low system usage
                                  adamjgan Level 1

                                  Hi guys.


                                  I have since purchased x4 Samsung Spinpoint HD103SJ disks and put them in a RAID10 (BIOS controller). I have read several articles on the internet about which RAID level to use. Using HD Tune, I get an Avg. of 205Mbps, Max 290Mbps and Min. 130Mbps on the RAID10. The articles I have read seem to heavily weigh against RAID5. When I configured these drives in RAID5 the benchmark failed to run unfortunately. Would you think that these performance figures will be adequate for running Premiere Pro 5.5? Should I change over to RAID5?


                                  I will re-run the PPBM tonight to see if this new array can beat my score of 435!

                                  • 14. Re: Choppy video despite low system usage
                                    Harm Millaard Level 7

                                    Striped and mirrored arrays are OK from the mobo, parity raids should only be run from dedicated raid controllers. As a very rough rule of thumb, the speed of a parity raid is somewhere in the region of 0.75 x (individual speed) x (N - P) where N is the total number of drives and P is the number of parity drives, so P = 1 for raid3 or raid5 and P = 2 for raid6.


                                    Example: 4 disk raid3 or raid5. Speed of a single disk 120 MB/s. Speed of the array is 0.75 x 120 x (4 - 1) = 270 MB/s. Adding a disk to the array increases that number by 0.75 x 120 = 90 MB/s.


                                    This is a very rough rule of thumb but indicative of the expected speed.