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Wishgranter

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performace question
« on: December 13, 2011, 08:44:35 PM »
Hello
im want to know what code is running on the GPUs, is that a SinglePrecision or DoublePrecision arithmetics ?
Why im asking ? because the NVIDIA card - gamer models - are by drivers disabled for maximal speed in the dubble precison - only to 1/5 of ther real performance. Full performace is only with the profesional like Quadro or Tesla cards
the AMD drivers are not so blocked, full DubbPrec FP power
 or the software use a Single precision FP arithmetics ??????
 
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Alexey Pasumansky

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Re: performace question
« Reply #1 on: December 14, 2011, 03:22:30 PM »
Hello Wishgranter,

PhotoScan uses single precision arithmetics in the GPU processing part (actually the most time consuming calculations are done even using integer arithmetics).

So the double precision performance limitations of the consumer video cards doesn't affect the processing speed at all. Consumer GeForce video cards should be as fast as professional (Quadro or Tesla) ones for PhotoScan.
« Last Edit: December 14, 2011, 03:28:29 PM by Alexey Pasumansky »
Best regards,
Alexey Pasumansky,
Agisoft LLC

Wishgranter

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Re: performace question
« Reply #2 on: December 14, 2011, 07:00:08 PM »
hmmm that good to hear, now is it just wehat card is faster in SinglePrec - ATI.....

THANX
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Wishgranter

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Alexey Pasumansky

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Re: performace question
« Reply #4 on: December 14, 2011, 07:32:55 PM »
Hello Wishgranter,

But despite of GFLOPs we recommend to use nVidia graphic cards because currently PhotoScan optimization for ATI graphic cards is not as good as for nVidia.

Our recommendation in relation of performance/cost ratio is GTX 580.
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Alexey Pasumansky,
Agisoft LLC

Wishgranter

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Re: performace question
« Reply #5 on: December 14, 2011, 08:50:40 PM »
Yes, the Nvidia cards are standard, using the 560ti, but in one-two months are the new 7xxx line from ATI on market, with their GCN - GraphicsCoreNext, from what is for study about this, they should be very well optimized for our stuff - GPGPU use, therefore a lot of performance gain, but as history learn us benchmark should let us know what the best, im preparing a scene for benchmark that is nice and is useful - that we can compare what the best.......

another issue what i get notice, i tested a mesh with around 35 mil triangles, and it seems that new drivers slowing down viewport, but must go deeper over Christmas where is the problem.....
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