Asus U3S6 USB + SATA PCIe card

Asus has a list of boards that the card is compatible with, but users are reporting much wider compatibility. Well, I tried it on my Asus X48 board that had a spare 16x PCIe 2.0 slot open... and no dice on the USB 3.0 (the SATA controller seemed to install though).

I then tried it on an old P35 board with a "16x" slot that was electrically a 4x PCIe 1.1 slot, and it worked fine.

So, I can't say for sure it doesn't work in PCIe 2.0 slots... but something to keep in mind.

*Update* I looks like it was due to an overclocked PCIe bus. I ran into the same problem with the Gigabyte 3.0 card on the same board. I kept scaling the PCIe speed back until 103Mhz, at which point the NEC USB3.0 controller sprang to life. So, keep in mind, the NEC USB controller won't take higher than 103 MHz on the PCIe bus, at least from what I've seen.