Since I had a number of spare Sata laptop drives sitting around I decided to purchase an external enclosure to make use of them. After testing 3 enclosures with USB, FW400, FW800 and eSata on my MBP and 2009 Mini, I'm not seeing any increase in data throughput between Firewire vs. USB. The drive I'm using in the enclosure is a 120gb 5,400 rpm Hitachi drive that was OEM in from my 2009 Mini. I replaced that drive with a 500gb 5,400 Hitachi in the Mini and my SR MBP has a 320gb Scorpio Black Drive. Both of these drives should be faster than the drive than I'm testing. First I bought an Eagle USB/esata enclosure (EAGLE ET-CS2XMESU2-BK). This is a nice enclosure with a very simple eject system. I was using the BC338 card and was getting many kernel panics so I knew eSata wasn't a long term solution. I was able to run a few tests and the eSata connection appeared to be about 50% faster than USB in transferring data. Next I tried the Macally PHR-250cc which has many fine reviews. Several tests were showing the USB to be as fast or slightly faster than the FW400 connection to my MBP. I transfer both a 6gb folder as well as a 2gb xvid file. This was counter to everything that I had read about the superiority of FW vs. USB. Since the Macally was only FW400 I decided to get a FW800 enclosure since that would surely be faster. I purchased a Mapower MAP-KC21 FW800/USB enclosure. After testing the same drive I had the following results on my MBP and Mini for writing a 6gb folder to the external. MBP FW800 3:53 USB 3:54 Mac Mini FW800 3:42 USB 3:44 Can anyone explain why my FW800 connection appears to be no faster than plain old USB? My first guess was that the 120gb drive in the enclosure was the bottleneck, however, when I was using an eSata enclosure I was seeing faster transfer speeds. I don't know enough about the relative speeds of the various components of the system to know what could be causing the throughput to be the same. Based on my testing it seems I could save myself some money and purchase a plain old USB enclosure since I'm not seeing any benefit from FW. Any thoughts would be appreciated. Thanks.