470gtx+Quadro 4000 slower in octane when paired.

[Emcs07]

Hello everyone, I am trying out Octane Demo, beta 2.2.

I recently bought a Quadro 4000 and installed it today. When I tried running Octane with my 470gtx as an extra GPU device I noticed it was going slower than with the 470gtx alone, is this normal? When I use the 470gtx alone I get around 8-9 MSamples/sec and when I use them both I get around 4-4.5MSamples, in the same scene.

Any help is appreciated, thanks!

[pamana]

how did you enable x2 gpu's with the demo?

[Emcs07]

how did you enable x2 gpu's with the demo?

Hmm, I didn't know there was such a limitation. Anyways, here are the screen-shots:

[curriergroh]

Not exactly the same but it might help. I'm using a 4000 and a 460.
If you can watch the gpu usage with a monitoring program you will see the quadro running at max ~95-98% at stock clock (475MHz) and the GTX card will be running much lower like ~50-60% usage.
If you oc the Quadro (not a big deal. It is basically factory UNDERclocked. All of the other cards with the GF100 are shipped at ~600MHz or more stock.) you will see the usage of the GTX card increase. Below I posted my final state, but the usage of the GTX started at 55%. I think before the oc it was running at 1.8 megasamples combined.
EVGA Precision will let you adjust the clocks and fan speeds.

Quadro 4000 overclocked to 600MHz temp 77C usage 96%
GTX 460 overclocked to 775MHz temp 54C usage 72%

Megasamples 2.23
FPS 4.24

[Emcs07]

So Octane doesn't scale with multi-GPU unless all of the GPUs are of the same caliber? Meaning adding a 580gtx to this setup would be useless?

[curriergroh]

Further testing:

Two cards of different speeds...
The faster card can have its clock speed reduced to that of the slower card with no rendering speed loss
If that is done the usage will even out
If the faster card has a higher clock than the slower card it will be utilized less.

I knew that two cards would use the lowest common ram but I didn't know that they would also use the lowest common clock.
I found the fastest setting to be one where the faster card is down clocked to match the highest overclock of the slower card and then pushing the memory clock as high as possible.

Not really an issue for me. The purpose of the two card setup for me was to be able to model and render at the same time, so I'm only using one active card usually.

[Jaberwocky]

You may not be aware of it although it has been highlighted elseware on the forums but there is currently an issue with the GTX460.Until Octane is recompiled using Cuda 3.2 it is only currently using 224 of it's 336 available cores.A bit of a bug courtesy of Nvidia i'm afraid.Hence why you are only getting around 70% usage out of the 460 atr the moment.It's nothing to do with unpaired cards.
Currently Cuda 3.2 is in Beta i believe.As soon as Nvidia release it then anyone with a 460 will suddenly get a speed increase.Personally i am hoping 2.3 V6 will be it.

[curriergroh]

In my last post I didn't add a screenshot, which made it harder to understand what was already a brain twister.
The 70% usage is not related to the core issue.
The usage is from a 'rule' that uses the lowest common clock speed for both gpus. I say this based purely on my direct experimentation and I could be missing something.

Example with evidence:
I am able to overclock the the Quadro 4000 to 625MHz. (475 stock)
I am able to underclock the GTX 460 to 625MHz. (775 factory oc)
I do this with EVGA Precision.
When I do this the usage is ~even, as evidenced by screenshot.
Now if I increase the clock of the 460 beyond 600 no improvement is gained.
This is why the OP with a 470 running by itself is faster than with a 4000. It only does as much work as the 4000 is able to.
Since the op stated that it was less work than the 470 was able to do by itself I conclude that one 470 is better than 2 Quadro 4000 (untested logic).

The core issue could still be related and possibly hidden from my tests because the crippled 460 has almost the same number of cores as the 4000.
Even if this is the case the lowest common clock still applies but 'might' scale based on cores.

[Emcs07]

You may not be aware of it although it has been highlighted elseware on the forums but there is currently an issue with the GTX460.Until Octane is recompiled using Cuda 3.2 it is only currently using 224 of it's 336 available cores.A bit of a bug courtesy of Nvidia i'm afraid.Hence why you are only getting around 70% usage out of the 460 atr the moment.It's nothing to do with unpaired cards.
Currently Cuda 3.2 is in Beta i believe.As soon as Nvidia release it then anyone with a 460 will suddenly get a speed increase.Personally i am hoping 2.3 V6 will be it.

It's a 470gtx though, not a 460.

In my last post I didn't add a screenshot, which made it harder to understand what was already a brain twister.
The 70% usage is not related to the core issue.
The usage is from a 'rule' that uses the lowest common clock speed for both gpus. I say this based purely on my direct experimentation and I could be missing something.

Example with evidence:
I am able to overclock the the Quadro 4000 to 625MHz. (475 stock)
I am able to underclock the GTX 460 to 625MHz. (775 factory oc)
I do this with EVGA Precision.
When I do this the usage is ~even, as evidenced by screenshot.
Now if I increase the clock of the 460 beyond 600 no improvement is gained.
This is why the OP with a 470 running by itself is faster than with a 4000. It only does as much work as the 4000 is able to.
Since the op stated that it was less work than the 470 was able to do by itself I conclude that one 470 is better than 2 Quadro 4000 (untested logic).

The core issue could still be related and possibly hidden from my tests because the crippled 460 has almost the same number of cores as the 4000.
Even if this is the case the lowest common clock still applies but 'might' scale based on cores.

Yeah I am starting to see this might be the case. So no point in mixing high performing with low performing cards at all. You have to be using similar cards all around to increase performance, it seems.

Nice find.

[tfiproductions]

hello,

this is my first posting to your forum, please help...

i have a pc win 7 64 bit with a Quadro 4000
i am trying to run a geforce card in the 3rd pcie slot of
an asus p6x58d-e motherboard...

i use adobe Premiere Pro cs5
and want to use 2 gpus so i can use 4 monitors for a better workflow...

i was told that a quadro can't be with a geforce driver (like your 470gtx)
because the drivers will fight / not get along...

can you please post back informing me of what quadro4000 driver version you are using and what geforce driver version are you using...


any more advice, insight, help would be greatly appreciated

i am a newyorkcity high school English teacher helping students make music videos and personal dvd's to help get them into college

just need some tech support,

thanks in advance,

jeffrey