I noticed that on 2012 i7 there is a bluetooth controller on the USB bus, and also that both usb 3 drives and bluetooth can impact wifi performance to a variable degree. I apparently had a bad card which made wifi speed degrade to an unusable point, which I found could be worked around by removing USB and bluetooth devices and switching to wired mouse and keyboard. With the new wifi card this has been eliminated but I still see an effect on wifi speed when USB devices are used and/or bluetooth is enabled. Could be connection speed variation or Cablevision throttling repeated speed tests. (I use Speakeasy and Comcast for test.) At any rate, the whole thing has got me wondering about the USB bus in general and as it relates to bluetooth. Specifically, I'm wondering if the bus reverts to USB 2 when a wired input device is used.