Today we posted a story about enabling Quad SLI with beta drivers available on Nvidia's N-zone enthusiast website. The results were mixed and we were not impressed with the overall results. What are your feelings on Quad SLI?
Unfortunately the rendering power of these systems can't be fully realized until we rid ourselves of the massive CPU bottleneck. Seeing the Quad SLI systems fall behind the 'single' 7950 and occasionally the X1900XTX just screams a couple things: One being drivers; even though this is a solution that enthusiasts can purchase, it doesnt look to be a sane one other than to physcially look at four GPU's in your machine and smiling from the gratification.
Looking at that table of results, I feel as if Quad SLI loses more than it wins. However most of the victories for QSLI are only several frames a second. Are 4-7fps worth the $599 tag for another 7950? I cannot doubt that one of the GX2' is a great thing, however dual setup, and Quad SLI has some major growing pains and driver revisions before it comes out of this 'lab rat' stage of mere speculation and into the realm of producing acceptable results.
Granted I didnt comb the article with a magnifying glass....I only noticed Quad SLI taking a victory with FEAR and Oblivion, but again, not by more than a few frames. Which is where this leads us too; Much needed driver revisions and a large CPU bottleneck. Which we will have to wait and see how Quad core CPU's begin to aleviate this impact.
Like stated above though. By the time this is smoothed out, we'll see the next generation cards from our producers and of course a dual solution then will kill a Quad solution from now, without the extra $500.
Really, I just like the PSU they used for the testing. How cool would it be to bring your friends over and be like... "Yeah, this is my rig, my cold cathode tubs, my Crossfire X1900's, My C2D 6800 Exteme, my 4GB of XMS, my 4 Raptor X's and o yeah....a small refrigerator too.
You know, you'd think with all those GPUs, they could get some sort of HDR+AA thing going...
SLi doesn't change the hardware limitations.
Regardless of how many GPUs you added, they still need to either go through the ROPs twice or have the HDR or AA done in software (ala AOE3).
At this point what's nV's motivation to bring an ultra slow HDR+AA to market. If they did bring "some sort of HDR+AA" to market and it was 1/2 the speed of the ATi solution, what benifit would that offer above not having FP16HDR+AA , you still end up with ATi > nV, but you've wasted a ton of resources making essentially a hack/workaround that will never be able to be full FP16HDR+AA throughout.
I think people are going to have to look towards the next generation of nV for FP16 HDR+AA.
I <think> the newest drivers support HDR + 4x FSAA. I've got both enabled in Half Life: Episode 1.
I could be wrong though...
It's not an issue of HDR+AA but FP16HDR+AA, it will never change that nV can't do FP16HDR+AA simultaneously, but they have 2 work around, 2 loops through ROPs with int8 second time around, or else 1/2 done in software like AOE3.
HL2 uses a mixed method of HDR that involves the option of integer HDR, nV can apply AA to int HDR, just not FP16 HDR in hardware.
Basically, the driver overhead for quad sli holds performance back such that at lower resolutions, normal sli and even single cards perform better. As they indicate, it's only when using very high resolutions with 8xAA/16xAF that quad sli begins to shine. In fact, based on their benchmarks, the two quad setups have a 20-50% performance advantage over even the best normal sli or crossfire setups using such settings.
With only 4xAA, the normal sli/cf configurations dominate even with resolutions in the range of 1600x1200.
So if you are not going to use above 4xAA with high res, you won't see any benefit to quad sli at all, and may even see a decrease in performance. If, on the other hand, you are going to run some ultra high resolution with 8xAA, you will notice a definite improvement.