afo

SDK 2.3 and multiGPU

Discussion created by afo on Dec 17, 2010
Latest reply on Feb 15, 2011 by nou
First impressions on multiGPU for the new SDK in HD5970

Hi,

I would like to share some insights about multigpu in SDK 2.3 (WinXP32 & Linux64), and yes, I know that AMD officially doesn't support the second GPU on the HD5970, I hope they will give support before xmas 2011...

WinXP32:

cal findnumdevices shows 2 devices; clinfo shows 2GPUs + 1 CPU (in inverse order, now there is GPU data first and then the CPU data)

My application has a parameter on which GPU work; 0 for the first one, 1 for the second and so on; I used to have 2xHD5970, I moved one to another machine. If I use GPU 0,everything goes fine, if I use GPU 1; the application crashes...

Linux64

Again, cal findnumdevices shows 2 devices; clinfo shows 2GPUs + 1 CPU

if I open 2 terminals, two instances of the application using different GPUs can work and give correct results. But system performance drops down: moving a terminal window goes in slow motion (this didn't happen with SDK 2.2), the four processors in my system are working at 80% and ati-config shows 30%usage for the first GPU and 70% usage for the secong GPU (with minor variations).

I would like to know if someone see something similar or has different experiences. Thanks a lot

best regards,

Alfonso

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