3-Way SLI Is Here In A Big Way - TRi-SLI System Build and Testing

Article Index
3-Way SLI Is Here In A Big Way
TRi-SLi and 8800GTX Action
TRi-SLI System Build and Testing
Real Gameplay Tri-SLI Testing

Test System:

Our test system was put together with some choice parts and although we may have been able to acquire a QX9550, we believe the overclocked Q6600 offers pretty good performance at a price that is pretty popular.  Although we often push our CPU up to 3.2GHz, we kept it at 3.0GHz through testing and ran the FSB at 333MHz for a nice round overclock all the way around.  We had 2GB of A-Data Vitese memory as well as 2GB of Crucial Ballistix Tracer on the bench as well and this memory played nice together which is no surprise as these two kits are powered by Micron D9 chips.  Below is the full break-down of the test system.

  • nVidia Reference 780i SLI Motherboard
  • Intel Q6600 CPU overclocked to 3.0GHz (cooled by Zalman CNPS9500 LED)
  • 4GB DDR2-1066 Memory (A-Data + Crucial)
  • 2x 500GB Seagate 7200.10 HDDs in RAID 0
  • 2x XFX 8800GTX 768MB Graphics Cards
  • 1x eVGA 8800GTX 768MB Graphics Card
  • HSPC Top Deck Desk Station
  • Zalman 850W PSU
  • Ultra Products Power Partner 325W PSU
  • Windows Vista Ultimate x64
  • Latest WHQL Motherboard and Graphics Drivers


 CoD4 - TRiSLi



Building The System:

As I mentioned previously, building a 3-Way SLI system was painless.  We used a fairly recent install of Vista x64, dumped the motherboard and graphics drives, used drivercleaner to get rid of all the renegade bits and bytes then performed a fresh install of the latest drives that support 3-Way SLI.  Once Astrofox brought over his card, we rebooted, dropped the card in the slot, attached the massive SLI bridge and booted into Windows.  Once it detected the cards, the driver installation went as normal and the Control Panel offered us 3-Way SLI.  Note that you cannot simply disable one card and run Dual-SLI anymore - only single or triple.  In order to run 2-way SLI, you'll have to pull a card from the system.  As far as frame buffer goes, with TRi-SLI enabled we've not got 2214MB of graphics memory available.  That's right, over 2GB ready and waiting.  This is another reason why 64-bit Vista should be used instead of any 32-bit OS.


 Lined Up
Lined Up
3-Way SLI System
3-Way SLI System


3-Way SLI Testing:

If you are considering 3-Way SLI on your current display of 1600x1200 or similar, you won't see a large performance gain from adding the third card.  Where the extra horsepower really shines is on large 30" displays such as our Samsung 305T unit that pulls off a nice 2560x1600 4Megapixel+ display.  If you're a hardcore gamer and you demand flawless video quality without sacrificing performance, then you'll definitely be a candidate - if you have enough cash to drop on a full system.  We'll start things off by showing how a single, 2-Way SLI and 3-Way SLI scale on today's popular 3DMark 06.

Click for larger image


To be honest, I was surprised to see a performance increase with the third card when running the default 3DMark 06 at 1280x1024.  Scores increase a little over 1.28x with the addition of a second card and weigh in at 1.34x faster than a single card with 3-Way SLI enabled at this "low" resolution.  To make this upgrade worthwhile, you'll need to run higher resolutions with AA and AF enabled - which brings us to testing at 1920x1200 with 8x AA and 16x AF.  In this HD scenario, the 2-Way SLI shows almost a 1.75x improvement over a single card and the 3-Way system shows almost a 2.2x performance improvement over a single card - not quite the 2.8x nVidia claimed, but we're not done yet.  At 2560x1600 with 4x AA and 16x AF, a standard 2-Card SLI system shows 1.77x improvement and the 3-Way SLI system increases the performance to 2.3x that of a single card.

On the next page, we'll get into some actual game play testing and see if the performance holds up in the real world.