Multi GPU question

[CoCo]

Hi!
first of all, you guys made a really nice piece of software, I'm really waiting for the final release !

I tried the demo at the office and since we have some unused graphic cards i put a second geforce in my station.
So now i have a GTX 275 + 9800 GTX. Will this configuration work with multi gpu rendering ?

Since I don't see the "multi GPU" flag in octane, I guess it does not work .. so is there anything to do ?

[radiance]

The new beta 2.2 will come out tuesday and will offer multi-gpu rendering, compatible with your cards.

Radiance

[CoCo]

Cool =)
thanks!

[CoCo]

Ok i put a second card in my personnal machine.
so now I have a Geforce8800 GTS (640Mo) + a Geforce 8800 GTS 512.

I opened the benchmark scene (and the spaceship cene as well) and looked at the performance using one card and using both cards :there just no difference ..

I activate the second card in the device manager, and then I click on the scene node, I can see the "Multi GPU mode (2 devices)" text.. am I missing something ?

btw i sent my hardware key yesterday and didn't get my activation code should i retry ?
thx!

[radiance]

Ok i put a second card in my personnal machine.
so now I have a Geforce8800 GTS (640Mo) + a Geforce 8800 GTS 512.

I opened the benchmark scene (and the spaceship cene as well) and looked at the performance using one card and using both cards :there just no difference ..

I activate the second card in the device manager, and then I click on the scene node, I can see the "Multi GPU mode (2 devices)" text.. am I missing something ?

btw i sent my hardware key yesterday and didn't get my activation code should i retry ?
thx!

since it's difficult to figure out if i got and activated your key this morning (i had a whole list of them as usual, and people use difference emails/nicks),
if you still don't have it then i suggest you mail it again something might have gone wrong

make sure you don't have SLI and physx enabled in the control panel.

Radiance

[CoCo]

well there's something really..really strange !
first of all, about enabling/disabling physx : if I disable the physx then octane won't show up my second gpu, so I have to let it activated.

I made 3 tests based on the benchmark scene, I made a 1minute render and looked at the performance informations :

#1 test : only one gpu (main), Geforce 8800 GTS (640Mo)
=> 175/16000 samples/px - 1.66 Megasamples/sec - 3.17fps

#2test : both GPU activated, Geforce 8800 GTS (640Mo)+Geforce 8800 GTS (512Mo)
=> 170/16000 samples/px - 1.64 Megasamples/sec - 3.13fps

#3 test : only one gpu (second), Geforce 8800 GTS (512Mo)
=> 232/16000 samples/px - 2.24 Megasample/sec - 4.24fps



when i look at both GPU spec i see that the 512 card has more CUDA core than the 640 one (128 against 96, the clock is also faster), so the #3 and #1 results make sense, but i really don't understand the result of the #2 test.
i made screenshots in case

btw for the licence, I was sending the request from the wrong email..

[radiance]

i think these old 8000 series cards don't scale well.
also, are you sure you don't have SLI enabled ?

Radiance

[CoCo]

well I put the SLI bridge off .. so yes I guess it's disabled.
Actually there is no explicit SLI option in my drivers, just "multi gpu acceleration" (french traduction) or "Threaded optimisation", anyway I disabled these options.

[geo_n]

Just bought. Will any motherboard with support for sli be able to do multi gpu in octane? So I can set one gpu to render without changing anything in the bios setting or windows setting?

[Amplitude]

Your motherboard doesn't even have to support sli ( mine doesn't and it works beautifully).
Just be sure to have several PCI express slots with 16x or 8x speed and your good to go.
(and if octane has some trouble to see your second gpu the only setting to check out is the PhysX one in the nvidia control panel).

happy rendering