I used disk utility to make a raid array (disk spanning) of two 1tb drives into 1 2tb drive to use as a TM backup. One is a firewire 400, the other a USB2. My question is whether having two interface channels will affect the speed at all. While I know that fw400 is faster than usb2 for sustained transfers, presumably at tm backup will saturate it. Will having the USB interface in addition help? If not, why not? Is there any way to see the utilization of each bus? Thanks!