ASUS Rampage VI Apex Overclocking Motherboard Review

The Hardware Asylum Multi-GPU index is a portable set of data we can use 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 is not dependent on system architecture it can be applied to any motherboard regardless of processor or chipset generations.

Index: 4.75
Optimized: 4x
Max Support: 4x

Index: 4.5
Optimized: 1x
Max Supported: 2x

Index: 3
Optimized: 2x
Max Supported: 2x

NVidia SLI
AMD Crossfire

As indicated by the PCI Express layout chart there are a total of four 16x PCI Express slots on this motherboard with four of them using bandwidth earmarked for video cards.  Slot one will be the primary video card slot and will run at a full 16x when only a single card is installed.   With 44-Lane CPUs slot five (or three if you look in the manual) will also run at a full 16x making it a second primary slot.

Things get a little interesting with 28-Lane and 16-Lane CPUs where you can no longer run more than two graphics cards or, any card for that matter in the full length PCI Express slots.  I find it interesting that ASUS didn’t attempt a 3-Way configuration with the 28-Lane CPU instead leaving slot one at 16x while slot five (or three according to the manual) at 8x.  The 16-Lane CPU supports dual graphics cards at 8x each. 

For best video performance you will want to populate slots one and five with video cards and it would be worth the effort to ensure you get a 44-Lane CPU.