Hi. I'll explain what I'm wanting to do. I want to plug an external RAID hard drive setup into my Al iMac via FW800 (Taurus RAID II). I also want to plug an audio interface via FW400 in the iMac (havent decided on which yet). I understand that if both are connected, that the FW800 will only run at FW400 (as they are on the same bus). What I don't know is if this will cause the same sort of problems that occur when you have 2 x FW400 on the same bus... ie many audio interfaces seem to play up if there is anything else plugged in on the same bus. I do have several work arounds (either getting a USB audio interface... which is more limiting with choice... or getting an ADDA converter instead and using the optical outs/ins on the iMac). Can someone clear this up for me. Thanks.