Hello, From what I gather, Thunderbolt and Firewire 800 both send data in constant, steady streams while USB sends it in bursts. If this is true, it translates to unduly taxing the processor and potentially impacting operations. I'm planning on upgrading my HDD & putting my existing drive into an enclosure and want to get the best one for file transfer & active work. Is it worth the extra effort to find an enclosure that has both Firewire and USB? My Macbook Pro doesn't really feel all that 'Pro' to me just yet and I'd like to do what I can to not hold it back in the coming years. thanks for your help, .r.