Now there is an excellent question! With my Powerbook 1.5mhz I ran benchmarks on a LaCie “Big Disk” that has both FW800 and FW400. There was very little if any difference in the speed between the two interfaces. Perhaps it makes a difference on a Quad Powermac, but I doubt if it has much difference on anything else. In real world use, I can find absolutely no difference in the performance of the Disk on my TiPB using FW800 and my iMac iSight G5 using FW400. jg On 10-Jan-06, at 6:00 PM, John McDaniel wrote: > On Jan 10, 2006, at 4:31 PM, Dr Trevor J. Hutley wrote: > >> Now that I have a fast and big FW800 LaCie external disk for >> backup, I would really miss the FW800 port, especially as files >> and amount of data is continuing to increase. FW400 will just be >> too slow. > > Have you compared transfer speeds between FW400 and FW800 on your > system?