expresscard speed question

i've been reading quite a bit lately and realized that the 480mbps for usb is in bits which at best theoretically is 60 megabytes. i've tested speed for a few ide drives in usb enclosures and only got around 24 megabytes which is alot slower than when they were connected directly to the ide ribbon in the computer. so my question is on http://www.expresscard.org/web/site/qa.jsp in the speed section it explains how expresscards use usb 2.0 for the interface. if that's the case would buying a esata card to connect to a external hard drive give me the same performance as using a usb enclosure on my inspiron e1505?

Message Edited by shreaded_teddy on 09-24-2007 10:59 PM