GPU Acceleration intermittent issue

James81

• 18. April 2013 19:39

Hello Folks

I have a strange issue with Capture one 7.1.1 under Mountain Lion and Lion latest versions 10.7.5. and 10.8.x respectively.
Running on a 8 core 2008 MAC Pro with the GTX285 Graphics card 4gb Ram SSD Drive. Loaded with the latest CUDA Drivers.

Using the "GPU is being used test" i.e ( at 100% magnification and change to say contrast nothing else enabled) and you normally get 1st a pixelation of the image then it switches to GPU and subsequent changes are realtime smooth and sharp.

This is not the Case - some times it works and sometimes it doesn't its like 30/70 under 10.7 and not at all under 10.8 ?

Under bootcamp windows 7 64 bit on the same machine, same version of Capture one 7.1.1 for windows - it works perfect every time. And also appears to be quicker all round and a more stable which is freaky. ?

Ive tried Both 6.4.5 and 7.1.1 under both mac OS and found that 10.8 GPU won't work at all but under 10.7 is 30/70 sometimes it will kick in.

My 285 Card is listed under the recommended card for this mac and fully supported according to Phase One.

we have two identical macs in our studio so i tried the other one and the Same thing happens.

Windows works great fast snappy sometimes the tool interface elements under windows are a little jumpy and the zoom slider can be a bit temperamental - but overall it seems much more …. well stable. The mask drawing also seems faster too.

So …what gives ? Any ideas guys

Many thanks

James

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  James81

  • 19. April 2013 17:03

  CVM Compiler and phase one
  
  Could anyone please tell me why phase one launches this compiler - because this is what is causing the problem.
  
  When capture one launches 7.1.1 it starts up this compiler and this coimpiler takes up 100% utilize of 1 CPU Core - and this in turn then disables GPU Acceleration.
  
  Shortly when Compiler stops roughly about 60 secs you get GPU back again. - But the cycle starts again and you lose GPU.
  
  So how does this work maybe someone form Phase one Can Chime in ? 🙄
  
  Only tested this under 10.7 so far.
  
  Thanks
  
  James

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  James81

  • 19. April 2013 20:07

  OK Ive looked into this same compiler thing under 10.8 and its running the compiler but the GPU never kicks in and works.
  
  Ive also noted that under windows 7 64bit if you use the drivers that windows update suggest (GTX285 update) it kils the GPU acceleration on Capture one. Doing a roll back to the CUDA drivers for the card from Nvidia - its starts working again.
  
  So its very fussy this program on my mac pro bootcamp what Driver it works with etc.
  
  all very interesting but .....alas we still dont have a working system maybe someone can give the spec of a system thats using GPU all the time and i can build it - or a mac that does the same and we can by one for our studio.

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  Christian Gruner

  • 20. April 2013 13:55

  Some questions, what version of the nvidia drivers are you running ?
  
  What you see during startup is probably the init of the OpenCl. If anything fails or the card does return the expected values during this phase, we will not init the card, and thus CO will not be GPU accellerated.
  
  My best advice for you will be to get a newer faster card! The GTX 285 is pretty old. The number of CUDA cores in this card are low (240) vs a GTX 680 (1536 cores). On top of this the OpenCL version supported by the 285 would be lower than a new card. This also affects performance as newer version have more capabilities for CO to use.
  
  If you want the same family of cards as your 285 was in the beginning, consider a GTX 680 or a ATI Radeon HD 7950.
  Compared to your to your CPU-power, you wont get that much more performance out of the 285.

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