Opteron DD0201

Hi All

Very new to this forum, just registered today so be patient please.

I recently bought the above drive and cannot get it to burn faster than X2.
It came with f/w 2.17, so I upgraded to 2.50 but still no faster.
The box and website claim it is a 4X multi-burner.
I am using WinXP Pro (fresh install), Athlon XP2400, 512Mb mem.
Does anyone have any ideas?
Also, can anyone tell me what HD Burn is/does, as the website is not very helpful.

TIA
Bertie