XFX Triple SLI - 8800 Ultra's in 3 Way SLI Page: 1
SLI has been around for a few years and Nvidia have pretty much been the driving force behind multi-GPU solutions since the inception of their SLI solution. Last year they tried to ramp it up a notch with Quad SLI, but this failed to impress enthusiasts, review websites and pretty much the whole industry.
Now they've brought in another crazy solution: Triple SLI, or 3 Way SLI.
What you need for SLI, according to Nvidia is:
3-way NVIDIA SLI-Ready GPUs:
NVIDIA GeForce 8800 Ultra
NVIDIA GeForce 8800 GTX

3-way NVIDIA SLI-Ready MCPs:
NVIDIA nForce 780i SLI for INTEL
NVIDIA nForce 680i SLI for INTEL

3-way NVIDIA SLI-Ready Power Supplies:
Please visit the SLI Zone Certified SLI-ready Power Supply website and choose a power supply model from the section For “Three GeForce 8800 Ultra or GeForce 8800 GTX.”

3-way NVIDIA SLI Cases:
Please visit the Please visit the SLI Zone Certified SLI-ready Cases website and choose a cases from the section For “Three GeForce 8800 Ultra or GeForce 8800 GTX.”

3-way NVIDIA SLI Connector:
3-way SLI requires a unique SLI connector in order to operate properly. These connectors may not have been included with your previous purchase of SLI-ready components or PCs. PCs specifically sold as 3-way SLI PCs will have this connector included and preinstalled.
SLI...so what is it?
SLI stands for Scaleable Link Interface is the marketing name for a way of using two or more graphics processors in parallel. Using both the PCI Express bus and the proprietary SLI connector made by Nvidia, the graphics cards communicate using dedicated scaling logic in each GPU. Load balancing, pixel and display data are passed between each GPU over the PCI-e and SLI connector; basically the two cards share the workload.
SLI isn't perfrect, but it is improving as Nvidia revise and re-work their drivers and algorithms to get the best out of SLI. Most situations where SLI is supported see a 1.5-1.9x increase in performance, although unsupported games do not see any at all, some even having a loss in performance.
There are three different rendering or balancing modes for Tri SLI, below is an excerp from WikiPedia with the details:
* Split Frame Rendering (SFR), the first rendering method. This analyzes the rendered image in order to split the workload 50/50 between the two GPUs. To do this, the frame is split horizontally in varying ratios depending on geometry. For example, in a scene where the top half of the frame is mostly empty sky, the dividing line will lower, balancing geometry workload between the two GPUs. This method does not scale geometry or work as well as AFR, however.

* Alternate Frame Rendering (AFR), the second rendering method. Here, each GPU renders entire frames in sequence – one GPU processes even frames, and the second processes odd frames, one after the other. When the slave card finishes work on a frame (or part of a frame) the results are sent via the SLI bridge to the master card, which then outputs the completed frames. Ideally, this would result in the rendering time being cut in half, and thus performance from the video cards would double. In their advertising, NVIDIA claims up to 1.9x the performance of one card with the dual-card setup.

* SLI Antialiasing. This is a standalone rendering mode that offers up to double the antialiasing performance by splitting the antialiasing workload between the two graphics cards, offering superior image quality. One GPU performs an antialiasing pattern which is slightly offset to the usual pattern (for example, slightly up and to the right), and the second GPU uses a pattern offset by an equal amount in the opposite direction (down and to the left). Compositing both the results gives higher image quality than is normally possible. This mode is not intended for higher frame rates, and can actually lower performance, but is instead intended for games which are not GPU-bound, offering a clearer image in place of better performance. When enabled, SLI Antialiasing offers advanced antialiasing options: SLI 8X, SLI 16X, and SLI 32x (8800-series only). A Quad SLI system is capable of up to SLI 64X antialiasing.

Note that Tri SLI generally tends to use 3 GPU AF rendering and this certainly has the biggest performance benefit.
Triple SLI
Triple SLI works on the same precept as SLI, with 3 cards sharing the load. Unfortunately for the masses who went out and bought the excellent 8800 GT or 8800 GTS, Triple SLI supports only the 8800 GTX or the 8800 Ultra meaning that those without those expensive top-end GPU's will not see the benefit of Tri-SLI.
What do we have here then?
XFX have kindly sent us three of their top-end  8800 Ultra's to perform the review, along with their 780i SLI motherboard we reviewed previously.
SLI boxes
XFX 780i SLI
Oh, and not forgetting the larger one of the two connectors in this picture:
SLI bridge
We'll take a brief look at whats inside those rather large boxes, then get into the benchmarks!

XFX Triple SLI - 8800 Ultra's in 3 Way SLI Page: 2
Pictures - Tri SLI
Really we know what an 8800 Ultra looks like and we've seen what XFX's 780i looks like, but hell....let's get some gratuitious shots of Tri-SLI:
single card
Triple SLI  triple sli
triple sli 2  triple sli
triple sli
OK, enough GPU-porn, let's get on with some serious stuff!

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Test Setup
For this high-end Tri-SLI review we are going to use the normal graphics card hardware, but with a beefier PSU, DDR2 and a 780i motherboard. It's worth noting that a monster 1100w Tagan was required for the Tri-SLI system with an overclocked quad.
Intel Q6600 @ 3.6GHz
Noctua NH-U12P CPU cooler
2GB Cellshock PC6400 @ 800Mhz 4-4-4-12
XFX 780i SLI Motherboard
3 x XFX 8800 Ultra's in Tri SLI
Tagan 1100w Turbojet PSU
Hitachi 7K160 HDD
Games and benchmarks used
I tried to get as many games benchmarked in the time I had and hopefully I've covered a decent amount for all of you out there.
Synthetic Benchmarks

Please note all Synthetic benchmarks were run at stock settings; just as the free ones would be, as well as 1920 x 1200, with 4 x AA added. All benchmarks are repeated three times for consistency.

FutureMark 3DMark03
FutureMark 3DMark05
FutureMark 3DMark06

Gaming Benchmarks

All gaming benchmarks are run through at a demanding stage of the game with no savepoints to affect FPS. These are manual run-though's approximating 3 minutes and all gaming benchmarks are run three times through the same points for consistency. We hope that this gives an accurate and interesting depiction of "real-life" gaming situations. Note the resolutions and AA each game was run at.

All gaming tests were performed in Windows Vista Ultimate, under DX10 if available.

Call of Duty 4 - 1920 x 1200, 4 x AA set in-game
Oblivion - 1920 x 1200, 4 x AA set in drivers and HDR set on in-game. Settings on "Ultra"
F.E.A.R. - 1920 x 1200, 4 x AA set in game, soft shadows enabled
Bioshock - 1920 x 1200, all settings to maximum in-game
Unreal Tournament 3 - all settings set to maximum in-game
Company of Heroes - DirectX10 patch. 1920 x 1200 with in game settings as here.
Crysis - 1680 x 1050, all in-game settings set to "High" and "Very High for Tri SLI

Again, all game run-through's are repeated three times for consistency and accuracy.
I've used the latest official Forceware drivers and enabled Tri SLI, leaving the drivers to use the preset configurations for load-balancing (which seemed to be Triple SLI AF rendering).

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Futuremark - Synthetic Benchmarks
FutureMark - 3DMark03

3DMark03 is a benchmark that uses mainly a DirectX 8 featureset including several pixel fill-rate tests. I included this test in the review to see an approximation of how well old games will play on the current gen cards, as well as how well each card copes with the fill-rate tests. Tri SLI then, should surely rip this apart...
And it does indeed, 80k is a more than awesome score and even at 1920 x 1200 with A x QAA on it the score is still very respectable.
FutureMark 3DMark05

3DMark05 is a benchmark based on DirectX 9 with more advanced shading and bump-mapping techniques, as well as a tough CPU test integrated. As this is a more advanced test, we should see an improvement here too.
Not quite the same improvement in 3Dmark05 scores though, which is surprising. The thing to notice here really is the fact that the score hardly budges, even when a lot of AA and screen res is added into the picture.
FutureMark - 3DMark06

3DMark06 is a more complex 3D benchmark, using many of the more advanced techniques found in DirectX 9.0c such as utilising Shader Model 3.0 and HDR lighting to create a tough benchmark that stresses both the GPU and CPU. The most advanced of the tests, Triple SLI would do well to do well in this test.
Similar to 3DMark05, the '06 score isn't "amazing", though it is an improvement on the others. Again, the score seems to stay high even when subjected to a pretty intense 1920 x 1200, 8 x QAA.

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Call of Duty 4

Call of Duty 4 is a stunning DirectX 9.0c based game that really looks awesome and has a very full featureset. With lots of advanced lighting, smoke and water effects, the game has excellent explosions and is fast and furious, perfect for our test suite.
cod 4
Call of Duty 4 shows that the SLI setup really spanks the other cards, especially when you consider that 8 x QAA was applied to the scene in the orange coloured bars. Call of Duty 4 is truly a beautiful game at this resolution.

F.E.A.R. is a game based on the Lithtech Jupiter EX engine. It has volumetric lighting, soft shadows, parallax mapping and particle effects. F.E.A.R. is a little older game so Tri SLI should handle this well and look fantastic.
F.E.A.R again showed that Tri SLI really does well at the higher resolutions and AA. However, the other cards also managed to play at 4 x AA and 8 x QAA doesn't look too different here.

Bioshock is a game based on the Unreal Engine 3. It uses some DirectX10 features such as awesome water and smoke effects. The detail level in the game, combined with a frantic pace makes for an excellent benchmark. I've found Bioshock behaves strangely sometimes in benchmarks so it will be interesting to see how it does here.
Here, Tri SLI doesn't seem to make a huge difference to performance of the other cards, though the 8800 GTX has a little blip here.

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Oblivion is a game that really taxed all of the cards at the time of its release. Well over a year on and the current generation of cards simply fly through it. However, with advanced HDR, excellent draw distances, detailed grass and scenery as well as fantastic water/magic effects it's a good game to gauge performance for those who love RPG's. Tri SLI + 8 x QAA should look fantastic!
As you can see, whilst the 4 x AA attempt isn't anything to write home about, the run-through's with 8 x QAA were basically the same FPS and as I predicted, looked fantastic.
Company of Heroes

Company of Heroes is a WWII-based RTS game that has an enormous amount of world detail. I played a DirectX patched version of the game that gives modern GPU's a bit of a workout.
Company of Heroes DX10 sees the Tri SLI setup sitting pretty at the top of the board by a fair distance, pretty fantastic.

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Unreal Tournament 3

I have included UT3, even though it is another UE3 game as it is a fast, frantic and furious multiplayer mash-up experience. Using advanced DirectX 9.0c features, the Unreal Engine looks fantastic and runs on almost all half-decent modern GPU's making it an ideal all-round test.
UT 3
Tri SLI again shows that it does the trick with a high amount of AA, although the UE3 engine doesn't really need that much GPU horsepower.

Crysis has to be our most challenging benchmark to date. Running under Windows Vista and using DirectX 10 path, I tried running tri SLI at 1920 x 1200 at "Very High" settings, no AA and also at 1920 x 1200 "high" settings.
Tri SLI was unfortunately unable to play Crysis at "Very high" without AA without feeling laggy. Whilst the average FPS is 18, it was faltering and not easy to play with, dropping to 4FPS at points.
"High" settings was much more playable and looked great at 1920 x 1200, which is still higher than most other cards can comfortably play Crysis at.

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Gaming Experience
The gaming experience with Tri SLI was for the most part enjoyable. Crysis felt "almost there" in that it almost felt like the cards could push the frames but software was drawing the setup back. Now this is just me speculating (albeit with some experience), but I hope future driver revisions cure this.
In addition to this, remember that the next gen Nvidia cards that are Triple SLI enabled have had a lot of R&D gone into them to be able to work better, according to nvidia's partners, so here's to hoping!
However, there are some points I would like to make.
"Multi-card "stutter" is an issue on Tri SLI, as it is on other multi-card setups. Whilst the games bombed along in FRAPS, the actual experience doesn't seem to be such a great experience and looks similar to single card performance, even though the numbers are high. To see what I'm talking about, look here.
Heat is an issue with Triple SLI, the middle card can bug out if the temperatures get too high. I tested this in a fairly warm environment and this certainly causes shutdown during intensive 3D applications. Whilst this isn't a major gripe, I had to stick a fan in the PC, blowing air right in between the cards to fix this (and open the window!!). Obviously, those with water-cooling won't have this issue!
Power is a big issue with Triple SLI. The OCZ Powerstream I have shut itself down when trying to power a Tri SLI system and even another PSU which claimed to be able to handle the load didn't do it. Luckily my trusty 1100w Tagan did the business, but you have to factor this into the buying decision, so don't forget.
Read on to see what I think about Triple SLI overall...

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Triple SLI is a fantastic advance by Nvidia after the failure of Quad SLI> The results are a lot better than I was expecting and I was impressed at some of the FPS I got...even at this stage which I would definitely state is "early days" for Tri SLI.
Price is a huge concern. With 3 x XFX 8800 Ultra's and an XFX Nvidia 780i SLI costing a whopping £1442 at the time of release, this technology really is only for those who really invest in their PC's. Couple those parts with a PSU that can run the rig, a CPU that doens't hold it back too much, some HDD's, decent sound and an LCD capable of showing what Tri SLI can do and you've got yourself a nice tidy £3000+ PC...and that's not including if you've gone the sensible cooling route and chosen a decent water-cooling kit to go with it!
komplet RR  XFX 780i SLI
However, Triple SLI and SLI in general has always been a place that has cost a lot of money. The budget SLI setups aren't worth paying for over a faster single card and the top end ones cost a bomb. I suppose the point of Tri SLI really is that is shows off what Nvidia can do.
I feel like I have a lot to say this in the conclusion, but some of it is hard to explain. Driver updates should fix a few issues and the new 9800 series should produce some more compatible cards than we see now. Is Triple SLI worth the money? I don't think so right now - it's a fantastic tech demo and a fun toy for the rich, but it's not a practical graphics solution for even your well off enthusiast.
As such, I'm giving Triple SLI a "Performance Award" for being the fastest setup out there...at the moment.
The Good
+ Awesome performance
+ Crazy speeds
+ Excellent technology/idea
+ Looks funky in your PC
The Mediocre
* Hot as hell in summer
* Some odd driver issues
The Bad
- Requires a lot of power
- Costs the earth
Thanks to XFX for providing the cards and motherboard for testing
Green with envy? Want some Tri SLI crazyness in your PC? Tell us here