LaCie Rugged Safe Firewire Write Speed / Faster from a windows virtual machine?
I would be wary of accepting any sustained write speed test results from inside a VM as fact. Most VM architectures execute clever caching and other algorithms when writing to virtual disks. Try running the "dd if=/dev/zero of=/dev/sda bs=1024k" command from inside an empty Linux VM against a large virtual disk to see exactly what I mean (speeds far higher than your physical storage).

How are you testing the firewire drive from within the VM? Is the drive being passed through to the VM as a firewire device in Windows or as some other device/drive?

More details would be very much appreciated.