Tom's Hardware already tested it. This is how PCIe bandwidth scales the performance: http://www.tomshardware.com/reviews/pci-express-2-0,1915-12.html I wouldn't say we can talk about bottlenecking, even 4x (8x on PCIe 1.1) offers very good results overall. Meaning that you probably won't NEED PCIe 3.0, just as you don't need PCIe 2.0 right know. That doesn't mean is not necesary, because it does help a bit, the more the better, and as long as it is totally backwards compatible, and seems it will be, what's the problem? On another note, this interface's 300w are probably for Intel Larrabee, so that POS can run on a computer without requiring a nuclear plant by the side of your PC.