It’s been a trying time the past few weeks. I’ve been itching to finish up the three-way SLI rig that’s been tempting me from the corner of the eye all that time, only to be distracted by other, more pressing matters, as well as being sidelined due to “technical difficulties”. Nevertheless, I’ve been able to get some results, and the quite messy collection of power supplies, cables, and video cards have been humming along nicely.

                                            The whole, messy afair that nonetheless worked beautifully.

Setting up the rig was not quite as easy as I hoped, because of a couple of key items: firstly, the “casing” that was used was the Antec Skeleton, which we reviewed recently in our January issue of HWM. Setting up the components themselves was not very difficult, except for the lack of a backplate slot for the third 9800GTX+, space limitations for the same card when sliding in the Skeleton’s tray (it tends to hit the Antec’s fan housing), and the horrible, horrible difficulty of plugging in cables anywhere due to the many structural bits that surround the PC components and prevent the user from gaining a good handhold for plugging in or removing cables.

                                             Antec's Skeleton casing looks good and provides excellent airflow at the expense of easy accessibility when plugging in cables.

                                            Without a dedicated "hard" 3-way bridge, 3 separate bridges were used instead.

A second problem was the lack of a dedicated 3-way SLI bridge due to a miscommunication between the supplier and MSI in Taiwan – thankfully this was solved by simply plugging in the SLI golden fingers with different-length SLI bridges in a specific order – not a pretty sight, but then again this setup wasn’t to be entered into any PC beauty contests. A third problem was the lack of a computer LCD that could display higher than 1600 x 1200 – as we all know, such low resolutions wouldn’t be able to stress-test the 3-way SLI setup anyway, and give benchmark numbers that wouldn’t reflect the power of the setup. To solve this a resident (temporarily, at least) HD LCD TV was recruited for the cause – an HDMI cable was used to connect the PC.

                                            A Sharp Aquos 46" LCD TV was brought into play to try out 1920 x 1080 resolutions.

These problems are partly due to the new-ish nature of the rig – as well as the aforementioned difficulties with the Skeleton casing, the MSI X58 Eclipse board was also new, as was the Core i7 920 processor. Setup of these items involved making sure that the correct drivers were installed and that requirements were met, particularly in regards to power. To this effect, we soon discovered that we had a serious lack of power, as we did not have a PSU capable of running everything in our rig. (typically, 3-Way SLI rigs require at least 1,000W, preferably 1,200W or more).  Running two Odin PSUs of 550 and 610 power ratings couldn’t cut it, and it was only after adding a third PSU, our trusty Antec Neo 480, to the rig was I able to remove the pesky Nvidia warning regarding lack of power for the videocards. Needless to say, the whole setup was a combination of octopus and bramble vine, but thankfully ran smoothly once set up.

                                            Two additional power supplies in addition to the installed 610W Odin provides power for the 3-card setup.

                                             Plugging in the power cables for each card proved to be an exercise in dexterity.

Problems solved, installation began in earnest, with the most important discovery being that 3-Way SLI only works with Vista, and thus instantly abolishing the usefulness of half of our benchmarking suite. In its place, we were left with some key tests – most notably a new, very scalable test in the form of Far Cry 2 by Ubisoft. After the requisite patching (Vista SP1, the 1.02 patch for Far Cry, plus the latest drivers for the 3-way setup – 181.20) we finally got the benchmark running at a good clip, and by this we mean a very big increase from a single 9800 GTX+ card running the same benchmark. 3DMark Vantage was also set to work, as well as Company of Heroes, although this particular benchmark only brought woe, requiring an endless stream of updates yet at the end still not delivering an acceptable level of increase in its bench numbers.

                                            3-Way setup under testing using the built-in CoH benchmarks. Results were later scrapped due to lack of time.

Far Cry 2 was designed to be a very scalable game, both in terms of hardware and settings. At 1440 x 900, a setting usually used on 19” wide LCD monitors, the 3-Way setup did not fall below 57 fps, giving buttery-smooth gameplay at all points in the “medium ranch” demo, with settings set to “High” and “Bloom” and “HDR” turned on. A maximum frame rate of 242 fps was reached, resulting in an average fps of 126 fps – remember that this game is practically new, and that the 9800 GTX+ is hardly the latest card from Nvidia. Comparing it to a single 9800GTX+, tested in the same rig, gave an average of 72 fps, with the numbers ranging from a minimum of 48 fps to a maximum of 129 at the same setting as above. A 1680 x 1050 setting was also ran, but we will be concentrating on 1920 x 1080, a setting that should be able to properly stress a 3-Way setup and a popular HD resolution, as well as the highest resolution that could be achieved with our loaned Sharp HD LCD TV. The same settings as above were used except for the resolution.

                                             Results for a single 9800GTX+ running at 1920 x 1080 resolution, High settings, no AA.

                                            Results for 3-Way 9800GTX+ SLI setup running at 1920 x 1080 resolution, High settings, no AA.

An interesting fact emerged from this test – while the 3-Way SLI setup achieved maximum fps results much higher than a single 9800GTX+, the minimum framerate achieved by both the 3-Way and the single card was only 1 digit away – and the 3-way SLI setup actually achieved the lower number. The single card achieved 37.75 fps minimum, while the 3-Way setup got 36.70 fps. Both are “passing marks” as far as smooth gameplay is concerned, and this points to either how well-optimized the game is, or to how we may need to test at still-higher resolutions in the future to further differentiate the level of settings in our benchmarks.

The 1920 x 1080 test gave an average of 60 fps and a maximum of 105 fps for the single 9800GTX+, while the 3-way got an average of 108 fps and a maximum of 250(!) fps. Subjectively, the tests looked absolutely beautiful, with especially realistic-looking flames and very well-rendered leaves swaying realistically in the simulated breeze. Light and shadow was used effectively in most scenes in the benchmark – giving the whole game a believable aura of realism. On the down side, jaggies were evident however, as no anti-aliasing was used for this round of tests.

                                             Test settings for the "max-level" benchmarking.

The next round of tests focused on maximizing the use of the 3-Way setup’s processing power – I ended up with 1920x1080 resolution coupled with all settings at “Very High” (an “Ultra High” setting was also available), and 8x anti-aliasing. Even here, the minimum framerate differed by only 1 frame – 7.77 fps for a single GTX+ compared to 8.93 fps for the 3-way. Average frame rates underlines the advantage of the 3-Way SLI setup however – even at these high settings, a playable frame rate of 30 fps was achieved by the 3-Way setup, while the single 9800GTX+ card only achieved 20 fps – an unacceptable number.

                                            Results for a single 9800GTX+ running at 1920 x 1080 resolution, Very High settings, 8x AA.

                                             Results for a 3-Way9800GTX+ SLI setup running at 1920 x 1080 resolution, Very High settings, 8x AA.

3DMark Vantage scores revealed a rampaging beast of a rig, with the “Performance” default setting giving 20,378 3DMarks, broken down into the 17,686 GPU score and the absolutely amazing 37,500 CPU score. The Core i7 processor comes to fore here – this is the highest score we’ve seen in the CPU sub-section of 3DMark Vantage. The closest number we had in our benchmark library was the one achieved by a Palit 4870 X2 – 8283 3DMarks and a GPU score of 12,217. The “High” default setting gave us 13,347 3DMarks with 11979 GPU.

                                             Also along for the ride were the MSI X58 Eclipse, a Core i7 processor, and the Antec Skeleton performing its maiden role of secondary test bench.

In the end, the wait was more than worthwhile. Testing for the 3-Way SLI brought together at our office some hard-hitting components such as the recently-reviewed Sharp Aquos LCD, the Core i7 processor, the MSI X58 board, and the Antec Skeleton, which by now has thoroughly frustrated this reviewer, although I admit that it is still much better than a standard tower for multiple swapping of parts and cooling, as long as you did not need to connect two or more power supplies to your rig. Conversely, it was the 3-Way SLI rig that did not quite surprise, as most of the benchmark numbers reached the expected level of performance.

                                            3 of these were the stars of the show; we're hoping for GTX285s for the next 3-Way SLI test.

What needs to be considered here is whether this kind of setup is practical for the PC enthusiast – for most of you, this question has probably already been answered depending on how dedicated you are to your PC-building and gaming pursuits. Taking into account the complexity of the setup (although this may be contested by those with a single very powerful PSU at their disposal), the cost (definitely not to be contested by anyone), and maintenance concerns including power upkeep, the triple SLI setup can only be considered an expression of excess – though one that many will be willing to undertake just to see how over-the-top they can be.

                                             Preliminary testing performed with some enthusiastic assistants.

Putting aside the power concerns, cost, and setup difficulties, 3-Way SLI is a wonderful technology that is able to scale the available processing power well enough to run some of the most demanding games available currently, and certainly most of the upcoming high-polygon games that are coming out.