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View Full Version : Using GTX's and FX's in the same time



Aselert
11-28-2011, 07:29 PM
Hi,

Is it possible to mix on the same motherboard Quadro FX graphics card (onboard memory for high and the best management 3D) and GTX (for the high number of CUDA core) with Bunkspeed software? I've seen similar configurations but I do not know if it works for our software ...
In fact, I would like to build a PC with a Quadro FX5800 with three GTX 590 at the same time, do you think this is possible?

david.randle
11-28-2011, 08:20 PM
HI Aselert -

We dont recommend doing this but after i describe to you how our software works, you won't want to mix these anyway.

So, in this scenario the item you must be most concerned with is VRAM. VRAM is not additive, meaning that you can's simply take 4Gb on the 5800 and add it to the 1.5gb x 3 on each 590. With our software, the scene must be loaded into EACH GPU's VRAM. Because of this, you are bound by the weakest link, so, just having a 4GB card isn't going to allow you to open a scene that won't fit into the 1.5gb on the 590s.

Also, the other thing you must be concerned with here is the generation of chip in the GPU. The 5800 is pre Fermi which makes it much slower than any Fermi based cards (all the new Quadro 4000, 5000, 6000 and Geforce GTX 400 and 500 series cars are all Fermi based). When mixing a non Fermi based card with Fermi based cards, our software will spend more energy trying to balance the workload between the imbalanced cards that it will hurt your performance more than if you were to just run the 3 590s.

I hop this all makes sense

Aselert
11-29-2011, 08:56 PM
Thanks David for your reply, it's very clear now! :)
I think I will buy a quad gtx 580 3gb to have a homogeneity and compromise between Vram, Cuda... and price!

My best regards ;)

david.randle
11-29-2011, 11:51 PM
Sounds great...that will still be an extremely fast machine! BTW: our products support about 5million polygons per gigabyte of VRAM/RAM

andy
12-01-2011, 06:24 PM
I'd love to see the cooling on that machine. Please post some pics after you run it for a couple weeks with some renderings. Any more than 2 cards and you definitely need a specialized case and fan setup.

Also, good to know about the polygon count per gig. I need to create some sort of spreadsheet to figure out how to balance that out, or something that can show me a maximum render size. Bunkspeed just crashes on me if I go to high, and I have to close and open again.

Aselert
12-03-2011, 02:49 PM
Yes of course andy, when I'm ready I will post pictures of the machine ;)
But what you say David is interesting: 5 million polygons per gigabyte, it means that with my setup I would be limited to 3x5 = 15 million poly for the scene? Alternatively, with the hybrid mode, I might be beyond exploiting the memory (16GB on my pc, so 16x5 = 80 million poly)?

david.randle
12-03-2011, 09:36 PM
Aselert - Unfortunately, in hybrid mode you're limited by your VRAM as well, so in hybrid, you would be able to load ~15million as well. Rendering in straight CPU mode will allow you to use all your system RAM. You won't get 80million btw because of the overhead for Windows and other programs/services you have running. 5million per gig is a raw geometry estimate as well that doesn't account for textures. Textures consume a fair amount of RAM/VRAM so be aware of that.

Aselert
12-04-2011, 01:22 AM
Ok, thanks David! But it's a shame for the hydrid mode... However it is hard for me to imagine what represant a scene of 15 million polygon (I work in nurbs with Rhino, I haven't the habit).
I am a designer but I want to use bunkspeed's software for architecture as well, do you think it is really possible?

david.randle
12-05-2011, 03:25 AM
Yeah, its absolutely possible. iray is one of the best renderers for architectural scenes, especially interiors. just be prepared for some slightly longer render times. As far as polygon counts for architectural scenes...usually they are quite low poly unless there are lots of small details present like fruit in bowls, wine openers etc. etc.

andy
12-05-2011, 11:40 AM
Exterior Architecture scenes are pretty much a joke as far as how low in polys they usually are/can be. David hit it right on the nose. Appliances and furniture can also really add to the polycount. But you'll usually be well under a million polys for most of those unless someone is demanding a fully detailed set of bonzai trees in the window.

And yeah, once you're getting past 2GB of memory for a scene you're probably best off using CPU. Once youre get past 12GB or so, you'll probably want to up that 16GB of memory also. Any time you get too close to your total RAM you get Really slow times due to caching. This is in any application.

Aselert
12-08-2011, 12:40 PM
Again, thanks for those answers :)
A last one... may be I'm a dreamer (probably yes)... but could I create my "big scene" using CPU mode, lock it... and after render with GPU... ? :D

andy
12-08-2011, 01:06 PM
lock it? I'm not sure I follow.
If you are rendering in background, in Most cases, you should be able to use GPU as far as I know. Because that tiles automatically. But like I said, if you are running into too much memory, you are simply stuck with CPU. I think with something quite complex clients will be understanding at a fairly high rendertime though.
And if that's the majority of your work, you may want to invest in a dual xeon hexacore machine (should run you about 12K in the end). It sounds rediculous, but if you do renderings a few times a week that require CPU, it quickly pays for itself.

Aselert
12-10-2011, 06:11 PM
Ok thanks Andy, that's clear :)
When I said "lock it" it was just to say "to lock my scene before doing the render".
I will built my pc after during january, but I hesitate between water and aircooling...

david.randle
12-10-2011, 06:18 PM
Aircooling is much more reliable if you plan on keeping the machine around for more than 18 months. Watercooling is ok but stresses the processor so they typically don't last as long. Watercooled machines can be very quiet, although, the most noisy bits will be the GPU's when running full bore and those can't be watercooled.

If you want my advice, i'd say aircooled. That way you can keep the same reliable machine for a lot longer and simply update the video cards when new ones come out about every 18 months or so.

Aselert
12-16-2011, 06:58 PM
Thanks for your advice David.
A friend said me exactly the same and in addition to being expensive the watercooling is more burdensome in case of change of graphics card.
I think I will buy 4 GTX 580 MSI or Gigabytes, which are overclocked.

david.randle
12-16-2011, 07:02 PM
Sounds fun! that's going to be an extremely fast machine :-)

Aselert
12-16-2011, 08:45 PM
David, excuse me to ask you that here but did you receive my 2 last mailing post?

andy
12-19-2011, 11:11 AM
I'm thinking of putting together a machine with 4 cards as well, but am contemplating which box to use. All the gamer boxes have a HUGE fan on the side and that's probably not going to cut it. You really want something with separate compartments for PSU, CPU, memory, graphics cards and have front to back air flow for each of them.
I was looking at Jeff Patton's machine, he's a big iRay user, and he's using 3 Tesla cards, and a Quadro 6000. But gamer cards run hotter.

Unless you do something like water cooling I'd probably avoid anything overclocked. That'll probably just make heating matters worse. Good call on the 580's. That's probably the best "bang for your buck." 3GB of memory, but well under 1000 dollars where the Quadro 6000 is slower and has 6GB of memory for 4000 dollars. WOW.