If it has an eSATA2 (how is it called?) port?! then it's fast enough, I've got my Windows on an external HDD with esata2, there's no Problem with that, don't know about USB2

IEEE1394 / Firewire 400Mb/s
USB2 480Mb/s
eSATA2 /SATA2 3.000 Mb/s

it's only a sixth (hope this is right too -.- still too many Gaps[I meant 1/6]) of an eSATA2 port. But maybe it's enough. Can't try that out, because my Windows would be lame as shit I guess.