Dat72 USB2 backup extremely slow

[g00bli]

Hi i have just installed a replacement drive for a client. Their old drive used backup exec 8.6 however as it didnt seem to support the new drive i configured the backup using the bundled data protector express sse. The server is a G2 proliant ml330 running 2ksbs. Backing up 25 - 30Gb of data took about 20 hours! I installed a usb2 pci card but this only reduced it to about 12.5hours. Surely there is something amiss!? Any suggestions would be great.