Introducing the Multi-GPU Index

The Multi-GPU index is a portable set of data that we can assign to determine the multi-gpu potential of any motherboard.  A higher index number indicates a favorable condition for multiple graphics cards while a lower number indicates a hindrance in one of our leading indicators.  Since the Index does not take into consideration system architecture it can be applied to motherboards regardless of processor or chipset generations.

The data collected for each motherboard will consist of:

• Overall Multi GPU Index
• PCI Express slot layout (This will show you what each 16x card slot is doing as more and more cards are installed)
• n card optimized (This is to indicate the best performance configuration regardless of support)
• n card maximum (This will indicate how many graphics cards the board will support regardless of overall performance)

To help reinforce the findings of the Multi-GPU Index, we will be testing every board using  ATI/AMD Crossfire technology and mapping out the 3D performance results using 3DMark Vantage and 3DMark 06.

• Foxconn Quantum Force BloodRage
• EVGA X58 SLI LE
• Gigabyte X58A-UD3R
• Foxconn Quantum Force Inferno Katana
• EVGA P55 Classified 200
• DFI LanParty UT X48-T3R
• Foxconn Quantum Force BlackOps
• Gigabyte GA-890FX-UD5
• DFI LanParty DK 790FXB
• Foxconn Winfast NFPIK8AA

Unless otherwise noted all of the processors were overclocked to provide the same CPU score in our 3D benchmarks so to ensure the most accurate and repeatable GPU score.

We will be using the ATI Radeon HD 4850 512MB graphics card for the purposes of testing.  As you may know these are not the latest video cards you can buy but they have some unique features that are key to making this article work.

• Single slot coolers: while dual slot cooling solutions are more popular we needed a card with a minimal footprint due to the slot layout on some motherboards.
• Support the PCIe 2.0 standard
• Ability to run in QuadFire (quad gpu) configurations.

All of the cards will feature stock core and memory clocks; in fact the only thing we will change is the default fan speed to make sure they stay nice and cool.