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anyone used quad sli?

bluntslide

bluntslide

bluntslide

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25 Feb 2007
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leicestershire
hey all
im fixing a friends pc and i think when he ordered it, he went a bit ott.
its got two winfast 7950gx2's in sli and out of curiosity i thought i would run 3dmark06. with the gpu bar enabled it says quad sli but the result was a bit low, 8400? i removed a card and tried the single to get 8100!
further to this i put the spare card in my rig and broke 9000 so i think something is missing.
are there drivers to support quad sli? or has anyone got some experience with this kind of setup?
mobo is asus m2n32 deluxe with ocz 7200 sli ram, which can only run at 800mhz because of the board.
cheers
 
bluntslide said:
am2 fx64 or was it 62? either way it runs at 2.8
Click to expand...

I'll go with what the others said then.
Either way Quad SLI even when working, never worked paticularly well.
 
yeah i see what your saying, thanks for clearing it up.
he might as well make some cash and sell one while they can still fetch some cash!
 
Yeah - quad's pants.

My overclocked GX2 got 9331 in 3DMark06 coupled with an Opteron 165 @ 2.88ghz.

Great cards on there own! I needed to get an 8800GTX as the GTS's gave similar performance to the GX2. :rolleyes:

gt
 
As stated, quad SLI was extremely inefficient. Only in a few select cases did it offer any real improvement over regular SLI. Perhaps with better drivers it would have improved, but you've always get the law of diminishing returns when you try to couple ever larger numbers of systems together.
 
law of diminishing returns applys to gpus i guess.

with 2 cards you never get double the speed increase,

e.g single card would be 100%
double card would be 160%
3 cards could be 180%
4 cards would end up at around 195%

just an example to show you how it would scale. but as you can see its like a diesle engine at high rpm.
 
I played around with QUAD SLI and got much better scores than that in 3D Marks 06... one GX2 alone gets more than 1000 points higher than that... I can't really remeber what the 3D Marks 06 scores was for quad but it was only about 20% higher than one GX2 iirc.

I need to play around with it again sometime - but I had to borrow a card to test it... FEAR works pretty well as already mentioned and there are some other games that you can get to work well with it if you play around a good bit with nHancer... basically games that work well with both AFR and SFR in normal SLI you can get a good boost over a single GX2 with enough CPU horsepower, but if the game doesn't work too well with SFR (quite a lot don't) then its never going to work with quad.
 
Cyber-Mav said:
with 2 cards you never get double the speed increase,
Click to expand...

not entirely true - quite a lot of games that support AFR and benchmarks like 3D Marks get pretty much double the performance - a little is lost to overheads but its not more than 1%...

Games that only work well with SFR have very variable speed gains from nothing at all, to double but more realistically 40-60%...
 
The Quad SLI principle worked very well, in fact, and still does. However, the limitation (kind of a big one, really) came with DX9.

DX9 has issues with its frame buffer, in that it can only deal with three frames being buffered at any one time. As a result, having four frames rendered and ready to go netted no benefit whatsoever in DX9 games. Which is why games based on DX9 show very litte improvement or a decrease in performance with Quad SLI.

OpenGL yields a different result altogether: there is no limiting frame buffer restriction so the four GPUs can go all crazy, rendering as many frames as they like. As such, the results with Quad SLI + OpenGL were much better and more in line with a typical scaling model...

This doesn't mean Quad SLI was an outright failure: it provided impressive benefits for games based on OpenGL at ultra-high resolutions. It was next to useless for DX9, which is why so many people on here say "it didn't work" without really thinking about it.

There is, however, no defence on Nvidia's part: what they were doing pimping Quad SLI when they of all people should have known about the frame buffer limitations is beyond me. But, Occam's razor makes this one difficult: were they really so dumb as to suggest Quad SLI was the panacea when in fact - to those who bothered to find out - it was only a half-truth at best? Or was it a marketing ploy to get those with wallets bigger than their brains to part with that extra £400 for that badge on their cases? Either way, Nvidia wins, really: marketi coup de grace coupled with dominance in OpenGL.

And then they brought out the G80...
 
Anyone really care about opengl these days? Even ID software have moved away from it now that theyre developing for the 360 and are now using direct 3d. Only big name game i can think of that uses it coming this year is quakewars.
 
Gerard said:
Anyone really care about opengl these days? Even ID software have moved away from it now that theyre developing for the 360 and are now using direct 3d. Only big name game I can think of that uses it coming this year is quakewars.
Click to expand...
Workstation applications like AutoCAD, Maya, SolidWorks, ProE, etc use OpenGL heavily. Also any game that intends to run on anything other than Windows will need OpenGL support as well.
 
mrthingyx said:
The Quad SLI principle worked very well, in fact, and still does. However, the limitation (kind of a big one, really) came with DX9.

DX9 has issues with its frame buffer, in that it can only deal with three frames being buffered at any one time. As a result, having four frames rendered and ready to go netted no benefit whatsoever in DX9 games. Which is why games based on DX9 show very litte improvement or a decrease in performance with Quad SLI.

OpenGL yields a different result altogether: there is no limiting frame buffer restriction so the four GPUs can go all crazy, rendering as many frames as they like. As such, the results with Quad SLI + OpenGL were much better and more in line with a typical scaling model...

This doesn't mean Quad SLI was an outright failure: it provided impressive benefits for games based on OpenGL at ultra-high resolutions. It was next to useless for DX9, which is why so many people on here say "it didn't work" without really thinking about it.

There is, however, no defence on Nvidia's part: what they were doing pimping Quad SLI when they of all people should have known about the frame buffer limitations is beyond me. But, Occam's razor makes this one difficult: were they really so dumb as to suggest Quad SLI was the panacea when in fact - to those who bothered to find out - it was only a half-truth at best? Or was it a marketing ploy to get those with wallets bigger than their brains to part with that extra £400 for that badge on their cases? Either way, Nvidia wins, really: marketi coup de grace coupled with dominance in OpenGL.

And then they brought out the G80...
Click to expand...

Great post.

I still maintain that "not working in DX9" is akin to "not working", since 95% of games use directX. But thanks for the clarification :)
 
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