I have been doing some looking too. My wife has a similar ( Intel ) Gigabyte motherboard, 12 gig 1333 Ram. Etc. ( GA-X58A-UD3R ) Also very slow speeds from USB2 devices.

From what I can tell, the Gigabyte motherboard will load both USB 1.1 and USB 2 controllers through the BIOS, even if legacy devices are turned off and there are NO usb devices connected. That is why there are both the Enhanced and Universal controllers in Windows 7 ( The board is listed as having 12 USB 2.0 ports, 2 USB 3.0 ports ) I assume this is for compatibility with USB 1.1 devices and the OS chooses which to use based on device.

Like you , when I plug in a USB 2 device it transfers at speeds at slightly over USB 1.1. ( It even puts a 2 after the name of the device ) Going from device to desktop max of 15.7 MB/s, from desktop to device max of 2.04 MB/s.

I have tried changing settings ( turning on caching for the device, the default was off ) but no change.
I have been looking to see if Windows 7 has all the proper 64 bit drivers for ALL devices, and although they are not the latest ( SP1 not installed ) they are all correct.
I’ll keep looking.