2 Replies Latest reply on Jan 20, 2012 6:05 PM by corry

    2xHD 6970: Heavy lagging - long time problem

    rosmo01
      When running OpenCL Seti@Home Multibeam, system responds very slowly

      I have had this problem since I installed the 2 HD 6970  right after the release, and it only occurs when chrunching VLAR workunits.

      The workunits has between 0 and 1% CPU utilization, and overall CPU utilization is allways below 100%

      Excample of lagging: if I hold down "a"-key on keyboard, it will take almost 2 seconds for the letter "a" being written into Notepad, and will only write in "hops". So even in the least resorce-hungry application for writing text the OpenCL processing is overpowering normal operations.

      System:

      Windows 7 Ultimate x64 SP1, Catalyst 12.1, SDK 2.6.

      Regards,

      Morten

       

        • 2xHD 6970: Heavy lagging - long time problem
          nou

          GPU are not preemtive. they can't switch from task to task. so when you launch kernels which takes long time to finish screen doesn't redraw. but CPU is just fine and system can respond normaly via sound or network.

            • 2xHD 6970: Heavy lagging - long time problem
              corry

               

              Originally posted by: nou GPU are not preemtive. they can't switch from task to task. so when you launch kernels which takes long time to finish screen doesn't redraw. but CPU is just fine and system can respond normaly via sound or network.

               

              Precisely the problem.  AMD has plans to add GPU preemption, and if they continue on the fusion roadmap at the pace they are currently, this hardware support for preemption may be in there as early as the 8000 series cards (unless they decide to rename those).

              A quick/easy workaround since you're running windows 7, is to grab a non-AMD graphics card, hook your monitor(s) to it, and run it's drivers in XP Mode.  Then the AMD cards become compute only.  Or, if you have control over the source to the apps you're running on your machine, add a cheap AMD card, and just tell your app not to use anything of that generation card.  Either way, problem will be gone. 

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