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multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 2:42 pm
by ribrahomedesign
Hi there .
i just noticed that with my new scene ,rendered with pathtracing ,multiGPU is slower then one GPU ?
i have two identical GTX 285 and both connected to a PCI Expressx16 Gen
is this because its pathtracing a interior shot ?
thanks
Rico
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 3:37 pm
by radiance
this is usually because you have SLI enabled.
switch it off in your nvidia control panel...
Radiance
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 3:42 pm
by ribrahomedesign
Yes SLI is enabled ,but if i disable SLI , octane only recognice 1 GPU ?
Rico
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 3:43 pm
by Amplitude
disable sli but try with physX enabled
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 3:49 pm
by ribrahomedesign
i am sorry but i was wrong ,i dont have SLI ,but PhysiX is enabled ,if it is disabled octane does only recognice 1 card.
thanks
Rico
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 5:06 pm
by radiance
ribrahomedesign wrote:i am sorry but i was wrong ,i dont have SLI ,but PhysiX is enabled ,if it is disabled octane does only recognice 1 card.
thanks
Rico
are you sure there is no SLI option in your nvidia control panel ?
lower performance with 2 identical cards is 99% due to having SLI enabled.
(even without any hardware SLI connectors/bridges)
Radiance
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 6:52 pm
by ribrahomedesign
yes, i have no SLI option ,i dont know why.on my older machine with 2x 8800GTX i have the SLI option
shouldnt i have the SLI option on my new machine ?
regards
Rico
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 6:53 pm
by radiance
ribrahomedesign wrote:yes, i have no SLI option ,i dont know why.on my older machine with 2x 8800GTX i have the SLI option
shouldnt i have the SLI option on my new machine ?
regards
Rico
no idea....
maybe try installing the latest drivers from the nvidia main page ?
Radiance
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 7:00 pm
by Amplitude
what board are you using? maybe your chipset doesn't support sli at all... (which is irrelevant for octane anyway)?
Re: multi GPU slower then single GPU ?
Posted: Sun May 30, 2010 7:19 pm
by ribrahomedesign
i dont know what board i have ,
i have a look if there is a new driver available
thanks anyway.
Rico