I made the switch from RAID to 2 independent external 2Tb drives. The drives have a single USB 3 port. Over the holidays I get a new iMac. Currently on a 2007 iMac with only FW and USB2. Buying the new iMac leaves me dangling with my old TM backup system. Here's a further question concerning Time Machine. My ext TM drive is a LaCie Quadra. Currently the fastest port among the 4 is an eSata. I had an eSata card in the old G4 tower I sold recently. So I am down to FW400 and FW800 & USB2. I use the FW800 on my iMac as the connector. After the holidays I'll be buying a new iMac with TB ports and USB 3 ports. Should I just plug into the USB2 port on the LaCie (from the new iMac) and forget about speed? Amazone does sell a USB to eSata adapter for $30. Worth bothering with or not?