RAID 5 Backup

Win 2000 Advanced Server, RAID 5, using BackupExec 8.6 tape deck on server. to back up 44Gb it is taking 16 Hours, now i know this is not right and have tried various options but still no joy. Has anybody experenced anything similiar and found theresolution. Whilst backing up at night, it seems that the CPU is max out at 100%. All I have come up with is possibly something to do with the RAID 5 system. But other RAID 5 servers backup ok.

Anybody……!!!!!!??