High CPU Usage when burning Audio w/LTR-40125W

I’ve got a Lite-On 40125W w/WS05 firmware under WinXP. Now, when burning any audio CDs (mp3->audio) w/Nero there’s fairly high CPU usage (~50%). Now this happens when burning the CDs @ 16x!! This does not occur with data @ even 32x speeds (no 40x media avail)! DMA is enabled and functioning properly. This never happened w/my Plextor 121032A so I’m wondering why this happens w/the Lite-On. I’ve recently formatted my machine so I doubt it’s really software (unless it’s a Nero issue). Anyone have any ideas? Thanks!

If it makes any diff, here are my system specs:

ABit BX6 rev 1
PIII 600
WD 40GB as master on promise ultra 100 controller
WD38400 as master on primary
Lite-On LTR-40125W as master on secondary
Toshiba SD-M1402 as slave on secondary