I'm looking into USB benchmarking at the moment and this keeps coming up; since a search didn't return any hits here at TPFC, I decided to submit it to forum consideration...
HD Tach was a software program for Microsoft Windows (2000 or XP) that tests the sequential read, random access and interface burst speeds of the attached storage device (hard drive, flash drive, removable drive etc). Drive technologies such as SCSI, IDE/ATA, IEEE 1394, USB, SATA and RAID are supported.
As of September 2011, the latest version of this application (220.127.116.11) is still not fully compatible with Windows Vista or Windows 7. However, HD Tach works in Vista and 7 64-bit by running it in Windows XP SP2 compatibility mode.
Download links: http://www.softpedia.com/get/System/Hard-Disk-Utils/HD-Tach.shtml
A lot of people swear by its results -- also, it can be 'UniExtracted' and as long as I can see, has no apparent restrictions...