ASUS ROG Maximus IX 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: 3
Optimized: 2x
Max Support: 4x

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 three 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. 

For best video performance you will want to populate slots one and five with video cards.  Some weird stuff happens with the slot layout when slots one, three and five have video cards installed as the bandwidth of slot five is split between three and five.  This allows for proper 3-way card configurations but with diminishing returns since slot one doesn’t give anything up. 

The Apex supports three basic multi GPU configurations from the standard and approved 2-Way SLI and 4-Way Crossfire.  A third mode is one that I rarely talk about and is Quad SLI.  Quad is different from 4-Way in that while you still have four GPUs in SLI you are using dual GPU video cards and thus keeping with the NVidia two card limit.