A Look At Triple-GPU Performance And Multi-GPU Scaling, Part 1
by Ryan Smith on April 3, 2011 7:00 AM ESTThe Test, Power, Temps, and Noise
| CPU: | Intel Core i7-920 @ 3.33GHz |
| Motherboard: | Asus Rampage II Extreme |
| Chipset Drivers: | Intel 9.1.1.1015 (Intel) |
| Hard Disk: | OCZ Summit (120GB) |
| Memory: | Patriot Viper DDR3-1333 3x2GB (7-7-7-20) |
| Video Cards: |
AMD Radeon HD 6990 AMD Radeon HD 6970 PowerColor Radeon HD 6970 EVGA GeForce GTX 590 Classified NVIDIA GeForce GTX 580 Zotac GeForce GTX 580 |
| Video Drivers: |
NVIDIA ForceWare 266.58 AMD Catalyst 11.4 Preview |
| OS: | Windows 7 Ultimate 64-bit |
With that out of the way, let’s start our look at power, temperature, and noise. We did include our jury-rigged triple-CF setup in these results for the sake of a comparison point, but please keep in mind that we’re not using a viable long-term setup, which is why we have starred the results. These results also include the GTX 590 from last week, which has its own handicap under FurMark due to NVIDIA’s OCP. This does not apply to the triple SLI setup, which we can bypass OCP on.
Given NVIDIA’s higher idle TDP, there shouldn’t be any surprises here. Three GTX 580s in SLI makes for a fairly wide gap of 37W – in fact even two GTX 580s in SLI is still 7W more than the triple 6970 setup. Multi-GPU configurations are always going to be a limited market opportunity, but if it were possible to completely power down unused GPUs, it would certainly improve the idle numbers.
With up to three GPUs, power consumption under load gets understandably high. For FurMark in particular we see the triple GTX 580 setup come just shy of 1200W due to our disabling of OCP – it’s an amusingly absurd number. Meanwhile the triple 6970 setup picks up almost nothing over the dual 6970, which is clearly a result of AMD’s drivers not having a 3-way CF profile for FurMark. Thus the greatest power load we can place on the triple 6970 is under HAWX, where it pulls 835W.
With three cards packed tightly together the middle card ends up having the most difficult time, so it’s that card which is setting the highest temperatures here. Even with that, idle temperatures only tick up a couple of degrees in a triple-GPU configuration.
Even when we forcibly wedge the 6970s apart, the triple 6970 setup still ends up being the warmest under Crysis – this being after Crysis temperatures dropped 9C from the separation. Meanwhile the triple GTX 580 gets quite warm on its own, but under Crysis and HAWX it’s nothing we haven’t seen before. FurMark is the only outlier here, where temperatures stabilized at 95C, 2C under GF110’s thermal threshold. It’s safe, but I wouldn’t recommend running FurMark all day just to prove it.
With a 3rd card in the mix idle noise creeps up some, but much like idle temperatures it’s not significantly more. For some perspective though, we’re still looking at idle noise levels equivalent to the GTX 560 Ti running FurMark, so it’s by no means a silent operation.
It turns out adding a 3rd card doesn’t make all that much more noise. Under HAWX the GTX 580 does get 3dB louder, but under FurMark the difference is under a dB. The triple 6970 setup does better under both situations, but that has more to do with our jury-rigging and the fact that FurMark doesn’t scale with a 3rd AMD GPU. Amusingly the triple 580 setup is still quieter under FurMark than the 6990 by nearly 3dB even though we’ve disabled OCP for the GTX 580, and for HAWX the difference is only .2dB in AMD’s favor. It’s simply not possible to do worse than the 6990 without overvolting/overclocking, it seems.
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Ryan Smith - Monday, April 4, 2011 - link
There are 2 reasons for that:1) We can't immediately get another 6990. I know it seems odd that we'd have trouble getting anything, but vendors are generally uninterested in sampling cards that are reference, which is why we're so grateful to Zotac and PowerColor for the reference 580/6970.
2) We actually can't run a second 6990 with our existing testbed. The Rampage II Extreme only has x16 slots at positions 2 and 4; position 6 is x8. The spacing needs for a 6990CF setup require 2 empty slots, meaning we'd have to install it in position 6. Worse yet is that position 6 is abutted by our Antec 1200W PSU - this isn't a problem with single-GPU cards as the blowers are well clear of the PSU, but a center-mounted fan like the 6990 would get choked just as if there was another card immediately next to it.
We will be rebuilding our testbed for SNB and using a mobo with better spacing, but that's not going to happen right away. The point being that we're not ignoring the 590/6990 multiple card configurations, it's just not something we're in a position to test right now.
piroroadkill - Monday, April 4, 2011 - link
As long as it's in the works, that's alright. Seems like you have your reasons for it being the way it is.Rukur - Monday, April 4, 2011 - link
This whole technology is stupid with monitors.Why don't you stitch together 3 projectors for a seamless canvas to play a game ?
SlyNine - Monday, April 4, 2011 - link
"This whole technology is stupid with monitors." Do you suppose neural interfaces will be her soon. kick ass.Rukur - Monday, April 4, 2011 - link
Can you read more than one sentence ?monkeyshambler - Monday, April 4, 2011 - link
Interesting stuff, but for a 3 card SLI / crossfire what I'd really want to see is what the framerates are when every setting on the card is maxed.e.g. 24x AA 16x AF, high quality settings selected in the driver control panels etc.
supplement this with whats the performance on triple SLI with 3 1920*1080 monitors @ 4x AA
As lets face it if your going to spend this sort of money (and likely a watercooling rig too as theirs no way three cards are tolerable otherwise) you want to have a genuine show of why you should invest.
The current resolutions just will never stretch the cards or enable them to differentiate significantly from a standard SLI setup.
Hope we can see some of the above in a future article....
Rukur - Monday, April 4, 2011 - link
I tend to agree. How is maxing everything any worse then half inch monitor bezels all over your play area.The whole idea of eye infinity is stupid unless we all look through widows with 1 inch gaps while racing extreme cars.
How about some projectors stitched together for real people to actually try.
erple2 - Tuesday, April 5, 2011 - link
Wasn't there an analysis a while back comparing 1x, 2x, 4x, 8x and 16x AA? I thought that the conclusion to that was that there's no discernible difference between 8x and 16x AA, and the differences between 4x and 8x were only visible in careful examination of static images. Under normal play, you couldn't actually tell any difference between them.Maybe I'm just remembering wrong.
Also, I think that Ryan mentioned why they haven't yet done the triple monitor tests yet (lack of hardware).
DanNeely - Tuesday, April 5, 2011 - link
That's generally correct. Toms Hardware has run PCI restriction tests roughly once per GPU generation. The only game that ever really suffered at x4 bandwidth was MS flight simulator.PCIe bandwidth can impact some compute tasks. Einstien@home runs about 30% faster on a 460 in an 16x slot vs an 8x.
fepple - Monday, April 4, 2011 - link
With my two 5870s I have a wierd problem in crossfire. I have two screens a 24''' LCD and a 37'' LED TV. When in crossfire if I play video on the second screen it gets some odd artifacts of black(ish) horizontal lines across the bottom of the screen. Only solution i've found is to not have the cards in crossfire and plug the TV/Screen into different cards for watching stuff.Annoying, any thoughts?