Back again with another GPU question.
xmarine
Posts: 40
I have been searching the web for information on the use of multiple GPU’s in a single system. Specifically two NVIDIA GTX 1060 (6GB) cards in a computer equipped with Intel i7 CPU. So far I have not found a definitive answer on the subject. There seems to be conflicting points of view everywhere I looked. I have received some great information on this forum in the past few months so here I go with another question. I may have the option of installing two NVIDIA GTX 1060 cards in a new (Dell Alienware) system. My question is and so far I have not been able to find any specific information. Is there an advantage to running two cards in one system. In terms of performance utilizing more cores. And more importantly does DAZ Studio/IRAY render engine utilize multiple GPU installations to full advantage. The cards and question will be the 6 gigabyte version of the 1060. No SLI support on this particular NVIDIA GPU. Thanks for any and all information.
Cheers...
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Comments
You can run two GPUs in a system, but be mindful of:
1) Power connectors. The 1060s on up require additional power connections. I believe the 1060 is a 6-pin, so if you get two, you'll need two of these. Or use an adapter. Be sure your power supply can support both cards.
2) Physical size. These cards are double-width, and ideally need space above for adequate heat transfer from the fan.
3) Heat transfer. Be sure the case you use has auxilliary coling. Don't rely just on the fan in the power supply.
The advvantage for Iray is that the more cores, the faster your renders will be. This assumes the cards use a reasonably similar architecture and driver. You're doing fine if you have two cards of the same type.
I think if it were me, I'd get one 1070 now, which has about 1900 cores. Get a seconde one later. Or if you have a deal on the 1060s, go for that. You'll have about 2400 cores at the end of the day (version about 1900 cores for a single 1070).
Yes.
You can run as many Nvidia GPUs in your system as you want for Iray rendering... As long as you have the PCI-E slots and the power supply to run them all. (The cards do not need to be the same model)
Iray does not use SLI. (Having an SLI bridge atatched can posibly cause issues with Iray rendering)
The GPU's do not share Vram (The scene is loaded fully into the RAM of each card, If the scene fits then the card is included in the render)
Right now GTX 1060 and 1070 cards are selling at a horible markup because of crypto currency miners.
You might as well shell out the $500ish for a GTX 1080 or $700ish for a GTX 1080 ti right now. (even at the correct selling price 2x GTX 1060 6GB cards = same retail price as 1x GTX 1080. and 1x GTX 1080 will render faster than 2x GTX 1060 and the 1080 can fit a larger scene into it's ram)
Thanks Tobor and JamesJAB for the quick reply and very helpful information. Certainly addressed and answered all my questions. I had not even thought about the power connector issue. Also the cooling and larger space needed for two GPU's. After reading both your replies l believe I'll change plans and just build another system. That's what I have always done in the past. Thoughts of buying a prebuilt system was a compromise at best. I render architectural scenes primarily. Mostly the larger works from Stonemason and others. It's a challenge trying to handle them at times with my present system. A six year old AMD 6 core with 16 gigs RAM and the GTX 1060. I tried one of the smaller Quadro cards last year before purchasing the 1060. Unfortunately it was not up to the task.
Thanks again for your assistance. It has helped me make a final decision. I appreciate it.
Cheers...
This is exactly the question I came to ask. :-)
I think I'm going to wait a bit to see if the crypto currency stuff dies down any time soon. Right now I'm using a GTX 970 - which is **okay**. I think a 1080ti is what I'll end up with.
The GTX 1080 ti has not been part of the crypto currency boom... so far. It most likely has to do with performance per watt (electricity cost adds up when you have a warehouse full of computers running their GPUs at 100% usage 24/7, and the crypto currency game has everything to do with electricity bill vs calculations per second)
the cheapest GTX 1080 ti on newegg right now is the MSI Founders Edition for $699. That price is right where it should be.
For a couple of months I ran a GTX 780 and a 1080Ti in the same box while waiting for a second 1080. The Daz Octane plug-in (and Iray?) only allocates VRAM for rendering up to the memory limit of the *smaller* card. So renders only used 3Gb VRAM before out of core memory was needed, even though the 1080 had 11Gb. I eventually configured the machine so that Windows and apps used the 780 as the screen driver and the 1080 was used solely by Octane. This turned out to be a very effective compromise. When I got the second 1080 I dumped the 780 and now Octane can access most of the VRAM (approx 9Gb not the full11Gb) and is blisteringly fast. E.g. 5 HD G8F figures and costumes to 2000 samples in less than an hour.
I'd repeat the point Tobor made about cooling. An older 780 and motherboard both died a few weeks apart, I think because the machine was routinely running very hot for hours at a time (it heated my room very nicely). I'd bought a gamer-type chassis and fan but even so.
No, Iray uses each card on its own merits - if a scene will fit on the larger card but not the smaller then the smaller will be dropped but the larger will still be used.