Firewire 800 transfer rate very sloowwww...

I recently purchased a Lacie big disk extreme external hardrive http://www.mobileplanet.com/d.aspx?i=151350 ,It's a 1tb and has both usb and firewire ports, I've connected it via firewire 800,and the transfer rate is only around 15-20mbps....by far extremely slow...the manual says the transfer rate should be around 100-80mbps when connected via firewire 800...any ideas as how to increase this speed??

Here are the technical details about the transfer speeds:
Interface Transfer Rates (maximum bus speed)
FireWire 800: up to 800Mbits/s (100MB/s); FireWire 400: up to 400Mbits/s (50MB/s); USB 2.0: up to 480Mbits/s (60MB/s)

Right now my speeds are much lower than those figures, any ideas people??

 

One thing to try is to reinstall the 1394 firewire driver.

 

I did, no change....