The Standard X58 Competitors
One of the first X58 motherboards we tested, Asus’ Rampage II Extreme uses electronic switches to alter PCI Express lane width from dual x16 to x16-x8-x8 when a third graphics card is installed.
While it's certainly a formidable contender, our only major layout complaint was that the slot were all placed “one position too low” to allow three double-width graphics cards to fit into a standard seven-slot case. Fortunately, today’s test takes place on an open platform.
But the Rampage II Extreme wasn't the fastest Core i7 motherboard we’ve tested. For performance leadership we have to look to a less-ornate product, the Asus P6T.
By moving its x16 slots up one position compared to its highest-end alternative, Asus made the P6T almost perfect for holding a trio of dual-slot graphics cards within the confines of a standard ATX case. Preventing 3-way SLI perfection is its inability to shift lane width when a third card is present.
The Asus P6T has its top two PCIe x16 slots permanently locked in x16 mode, while the third slot always makes due with x4 lane width. The P6T is a fast, mid-priced board that we’ve never recommended for high-end 3-way SLI. It's much better suited for a two-way SLI or CrossFire configuration, but we're using it here specifically to measure the penalty associated with that third slot's x4 width.