"As standard, P35 offers sixteen lanes of PCI Express 1.1 bandwidth (meaning no PCI Express 2.0 support in this chipset) as a single PCI Express 16x slot for a discrete graphics board. However, this bandwidth can be split across two electrical PCI Express 16x slots to offer CrossFire support, and indeed this is exactly what ASUS has done with the subject of today's review - Insert and enable two ATI CrossFire capable boards into the P5K Pro and multi-GPU rendering is possible, with the PCI Express bandwidth split between the two slots, giving eight lanes of bandwidth to the primary slot and just four to the secondary slot. While this will impact performance in some bus bandwidth intensive scenarios (with ATI's Super AA mode being the primary culprit for such situations), in many cases performance should be broadly comparable to using two 'true' sixteen lane PCI Express slots."