We tested each motherboard together with an Intel Core i7 3770K processor, 4 GB (2x 2GB) Corsair Dominator DDR3-1600 CL8 memory, an OCZ Vertex 4 128GB SSD, a Cooler Master Real Power M850 power supply and Windows 7 64 bit.
The charts below have the results of our benchmarks. The scores are all fairly close together. The differences that are there are due to differences in bClk and the inaccuracy of the benchmarks. As you can see the performance of the Maximus V Extreme is in line with the other motherboards. The bottomline is, performance should not be the deciding factor when deciding which motherboard is best for your system, because the differences are insignificant.