WD My Passport Studio Firewire

[caen1]

I own a 320GB Western Digital My Passport Studio external hard drive, which supports both USB 2.0 and Firewire 800. Theoretically, is should achieve speeds of up to 800 Mbps, but it's never passed 150 Mbps on my mid-2009 MacBook Pro. Now, I know better than to expect the advertised transfer rate, but still, it seems way too slow, and I think there is something I could do about it. I just don't know exactly what. Any advice? Thanks in advance!