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MULTI GPU
Posted: Mon Sep 20, 2010 11:02 am
by tbansront
hi!
i'll buy a new workstation with a multi Gpu card (gtx 480) hardware solution
Will it work with octane render? octane will reconize my 4 gpu cards for rendering or it'll work with only one ?
best regards
thierry bansront
Re: MULTI GPU
Posted: Mon Sep 20, 2010 11:36 am
by pixelrush
Hi,
If your motherboard can accomodate multiple 2slot wide cards and your power supply is up to max power use and they are sufficiently cooled in the case Octane will happily run in all of them at once.
The vram would not be additive but the render would run almost x times faster.
In most cases you would want to use a basic card for the UI display and dedicate the 480's or whatever just to cuda for rendering.
Most likely the most you could fit on a mobo would be 3x 480 + the UI card.
You would need a 1200W power supply or more.
The other alternative is to look at the GPU-X expander - see the forum header for a link.
I would think you will need 8 or 12 gb sytem ram.
There is some useful info scattered about the forum re hardware but feel free to ask any questions.
We are a pretty helpful community

Re: MULTI GPU
Posted: Mon Sep 20, 2010 11:48 am
by tbansront
thank you for the answer!
i'll check with my provider to see the config he's thinking for my needs about the temperature of the machine and ask him to take a look to the xpander for octane!
thanks again!!
best
TB
Re: MULTI GPU
Posted: Mon Sep 20, 2010 3:00 pm
by adrencg
How about running a 480 + a 280? What's the driver situation with that setup? Will they conflict?
Re: MULTI GPU
Posted: Mon Sep 20, 2010 7:51 pm
by pixelrush
No the cards will use the same driver just fine.
If you are talking about using both the 280 and the 480 together on the same scene for the rendering task the 480 is going to be waiting on the 280 some since both cards have the same data loaded and contribute in parallel. The combined performance isnt going to be that of a 280 + 480 running alone.
Bear in mind too the vram available will be the least common amount so the 1gb of the 280 will be the limiting factor ie the 480 may have 1.5gb but you wont be able to use more than 1gb if they run together on the same scene.
If you already have a 280 you might opt for convenience to use it for UI duty while the 480 does the rendering but another option to consider might be to sell it and and buy another 480 and use a basic card for UI duty.
Another option would be to get a basic card for the UI but runs 2 Octane instances each rendering a different scene or perhaps one doing masks while the other does the actual image.
I believe this scenario is possible with the internet based license but I am not sure. Need to check on that.
It depends on how much rendering you need to do as to how far you want to go with setting up your pc specifically for Octane.
You might be content to find a second used 280 with a basic card who knows.
If you are adding a 480 in to a pc with a 280 investigate the power requirements as its likely you will need to upgrade the PS. Octane works these cards to the max so you need a decent power supply, something like 1000-1200W would be in the ballpark for 2x480 or 2x280
HTH
Re: MULTI GPU
Posted: Mon Sep 20, 2010 10:57 pm
by adrencg
Sounds like I may have been better off using 2x 280's.
Re: MULTI GPU
Posted: Mon Sep 20, 2010 11:18 pm
by pixelrush
Well not necessarily cos a 480 is at least twice as fast as a 280 and 2x280 together will be less than twice as fast as one.

so a 480 on its own will be a bit better than 2x280 performance wise.
plus, the 480 rendering alone will give you 1.5gb space as opposed to 1gb for the 2x280.
I think you will appreciate having the extra room.
I was just trying to present options and considerations.
A 280 and a 480 if you already have it will be fine , no driver issues either which was your original question

Re: MULTI GPU
Posted: Tue Sep 21, 2010 12:55 am
by adrencg
pixelrush wrote:Well not necessarily cos a 480 is at least twice as fast as a 280 and 2x280 together will be less than twice as fast as one.

so a 480 on its own will be a bit better than 2x280 performance wise.
plus, the 480 rendering alone will give you 1.5gb space as opposed to 1gb for the 2x280.
I think you will appreciate having the extra room.
I was just trying to present options and considerations.
A 280 and a 480 if you already have it will be fine , no driver issues either which was your original question

Hmm...but 2 x 460 would be faster than a single 480, and cost the same as the 480.
I just want to get the fastest option that my case can handle, without going over $500.
Re: MULTI GPU
Posted: Tue Sep 21, 2010 1:10 am
by [gk]
it would also give you a memory pool of 2gb over the 480s 1.5
Did I read somewhere that it might be possible to open up the last 48 cores on a 460?
in that case you would look towards at 672+96cores for 2 460's
or so..
Re: MULTI GPU
Posted: Tue Sep 21, 2010 1:39 am
by pixelrush
Yeah ok so GTX460 are going to run cooler, quieter and use less power for roughly the same cost and same performance. The quiet and cool might be attractive enough on its own. Its up to you whether you go for the 1gb or 2gb model but I think most people would go with the later for a little extra $.
As [gk] says there is some possibility the 460 can be more fully utilised under the coming cuda 3.2 so the combo may yield better performance for Octane purposes. We should find out about that fairly soon - it could be a decent improvement if we are lucky.
They are also fairly a compact card which might fit in your case better.
I would think if you want 2x460 then you should go with a basic single slot card like a GT240 or something for the UI which probably draws <50W extra and retire the 280.
If you have a decent PS something about 750W min with 4x6pin connectors would be ok to cover the draw.
You could put the money from selling the 280 toward the new 460's +240?
I guess its up to you to decide whats important to you or the most practical.
HTH
