Will NVIDIA's 3-way SLI Make us Stand Up and Beg for More?


Fitting three NVIDIA GeForce 8800 Ultras in an nForce 790i board is quite easy. That is until your better half sees the next month's credit card statement.

As of today, the ability to team more than two NVIDIA graphics cards for accelerated, parallel 3D game rendering requires some very specific hardware - namely no fewer than three GeForce 8800GTX or GeForce 8800 Ultra cards and either a 680i-, 780i- or 790i-based motherboard with the appropriate number of mechanical x16 PCIe expansion slots. System chassis and power supply requirements are no small potatoes either. A big case with plenty of cooling is a must and 1000W (or larger) PSUs become the standard when you decide to move up to play in these leagues. GPU overclocking takes on a completely new twist when you starting playing with this sort of power.

We decided to get a little creative and built a 790i-based system that included water-cooling on both the CPU and all three MSI 8800GTX cards. Full-coverage GPU blocks from EK Waterblocks were our components of choice, and going with 3/8" ID Tygon tubing meant we could use the shorter "stubby" barbs we would need if we wanted to have any hope of fitting things together so closely. In the end, our loop contained one D-tek FuZion CPU waterblock, three EK full-coverage GPU waterblocks, a single 2x120mm radiator from Cooler Master, a combination reservoir/pump also from Cooler Master, two inline thermal sensors, and about three feet of 3/8" ID and 5/8" OD clear tubing.



Yes, please.

Sure, our temperatures are not going to end up being that great, but we fit everything in a single case quite nicely and we only needed two medium-speed fans to cool the radiator and nothing else. At least our hearing would be safe. Check the sections on real-world gaming results to see how these cards stacked up against single and SLI GeForce 8800GTS 512MB (G92) configurations.


3DMark06
Synthetic Graphics Performance - QX9770

NVIDIA's 790i platform just barely manages to edge out Intel's X48 when it comes to single-card 8800GTX general graphics performance. Of course, this may have more to do with the slight advantage 790i has with the use of DDR3 over the DDR2 in the X48 board than anything else. Not surprisingly, the 8800GTS 512MB (G92) cards overtake the older 8800GTX cards quite easily. Keep in mind that we ran all of the GPUs at their stock speeds, as advertised by NVIDIA on their official company website. This removes any chance for performance variation due to different vendor's default clocks and allows us to test the cards as NVIDIA originally intended for them to be run.

NVIDIA's 3-way SLI shows only minor gains over a similarly configured 8800GTS (G92) SLI system - at 3.2GHz on our Intel QX9770 we only managed to outrun the pair of G92s by about 500 3DMarks. While the G92-based cards may have a core, shader, and memory clock advantage, the 3-way setup starts to pull away a little more as we ramp our quad-core CPU all the way to 4.0GHz. This suggests that the tri-SLI setup is starved for additional processing power, and more advanced architectures and higher computing speeds will be needed if we are ever going to experience the true potential this technology.


3DMark06
Synthetic Graphics Performance - E8500

Gains with 3-way SLI were smaller with our E8500; multithreaded driver optimizations may play a role in this. Since we know the 790i is quite capable of fully utilizing a 45nm or 65nm quad-core CPU, picking one up is any easy choice if you've got the cash and are looking for maximum performance.

CPU Overclocking Capabilities: The 45nm E8500 and QX9770 Exposed NVIDIA's Quad-SLI Graphics Makes a Comeback
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  • ATWindsor - Wednesday, March 19, 2008 - link

    I couldn't agree more, features is all well and good, but only if things works and are stable. No wonder people find it daunting to build a computer, even when you have done it several times you risk going into som "trap" with things not working the way it should, more focus on this in reviews please.

    AtW
  • theYipster - Tuesday, March 18, 2008 - link

    I agree with Lopri in every regard. AT needs to stop masquerading these technical showcase articles as reviews. In addition to what Lopri already mentioned, I would add that AT failed to a) address the long standing concerns held throughout the enthusiast community over nForce product quality (regarding the paragraph on PWM design... very undwerwhelming considering that it doesn't offer support to its claim) and b) failed to provide a fair assessment of the value proposition these boards provide. The article states that the 790i provides a noticeable step up in performance over previous generations, and that owners of previous boards would find upgrading worthwhile. This is a bold claim, as such an upgrade would cost nearly $1000 (when factoring in new DDR3 RAM) and would not even include a new CPU or graphics card. Yes, the NB runs a bit cooler and can OC a bit farther, but how and why is that worth $1000, even to the enthusiast who can afford it easily? Lets also consider the grander scheme of things. What worth is it for someone who enjoys the latest and greatest to spend $350 on a board when Nehalem will change all the rules in less than a year. At least previous generations (as well as Intel's X38) provide some shelf life.

    In any case, Overclock3d.net has a very informative review of the Striker II Extreme which covers almost everything Lopri mentioned.

  • ssiu - Tuesday, March 18, 2008 - link

    "The EVGA 790i Ultra also handled our QX9770 sample with relative ease. We were able to benchmark and play games without incident at 400MHz FSB, our mark of excellence when it comes to quad-core overclocking."

    That is a low standard of excellence for a high-end chip. The Q9300/Q9450 overclockers are going to cry.
  • greylica - Tuesday, March 18, 2008 - link

    Mwahaha, some will say :
    " Now we can finnaly play crysis ! "
    Well done, 66 fps...
  • n0nsense - Tuesday, March 18, 2008 - link

    We can for a very long time.
    I do it with 1920x1200 at all Med + 4AA
    I have the 680i (P5N32-E SLI) + E6300@2.8GHz (not the maximum, but lower fan speed = less noise) + 4GB OCZ ReaperX @ 800MHz 4-4-3-12 1T and single reference design 8800GT from ASUS at stock clock (the only modified sing, is stock cooler replaced with Arctic Cooling Accelero S1 which reduced card temp by 25C)
    As you can see MB - year old, CPU 1.5 years old.
    I can't tell you the exact fps, but it's completely smooth playing.
    I expect next generation to bring same smooth play at all very high + all filterings for existing games.

    BTW, where 9800x2 in SLI tests on this 790i ?
  • SpaceRanger - Tuesday, March 18, 2008 - link

    When do you think nVidia will be putting out these boards for AMD CPU's. The only thing I see for AMD CPU's are boards that support CROSSFIRE, but not SLI.
  • ap90033 - Tuesday, March 18, 2008 - link

    It just costs to MUCH. I got 8 GIGS DDR2 800 an E8400 and a Single 8800GTS 512 meg, and I have the CPU Running at 3.6 (I am looking to try 3.8 maybe) and I can play any game maxed except Crysis. I can play it at high at 1024x768. I looked at SLI but its to danged expensive, I had 1220$ to spend and decided to get the most performance for the money. I wish they would quit going up in price on these motherboards, hey Nvidia, you do know I can get a GREAT Overclockers motherboard with good features (NO SLI OF COURSE) for $80 right? Why would I pay $250+ more for the board, another $200+ more for DDR3 Ram, and another $250 for another 8800GTS just so "some" games would run 15% faster? Are you nuts??? 10-15% but it costs like $800 MORE???? I think Ill save my $800 or so and use it on my next video card upgrade, my next CPU upgrade, and the next video card upgrade after that! LOL
  • krnmastersgt - Tuesday, March 18, 2008 - link

    Because this isn't meant at the people that want the best price/performance, this is for the uber-high end user, the extreme benchmarker/extreme gamer, of course by your logic SLI and CrossFire are stupid wastes of money since the performance doesnt scale linearly, but this is meant for enthusiasts and therefore you shouldn't compare it with something like a P35 board.
  • crimson117 - Tuesday, March 18, 2008 - link

    As an example, I was helping configure a Dell for a home office user, non-gamer, no video editing, etc, but he was fairly well-off money-wise. While picking options, at one point I said something about some component being "plenty for most users" and he replied (in a nice way) "I'm not most users"; so we went with the upgraded version even though the price performance, especially for his usage pattern, didn't make fiscal sense.

    The moral is there are people out there who get satisfaction over having the absolute best no matter the price.

    Relatedly, an experiment found that people perceive $90 wine as tasting better than $10 wine, even when it was secretly http://www.news.com/8301-13580_3-9849949-39.html">the same exact wine.

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