Booting from an external SSD
As you know with SATA connection you get 3 to 6 Gb/s.

With Firewire you get &lt; 1 Gb/s data transfer.

To be specific:

Firewire 800 is 800 Mbits/s (Mb/s) not 800 Mbytes/s (MB/s) [8 bits in a byte] its a common misconception. so Firewire 800 is rated up to 80 MB/s.