My hard drives are fine, ive done this while they were being moderately used and even heavily used before and been able to burn CD's/DVD's ok.
Now whenever I burn anything, be it CD or DVD (been using the same media spindles for quiet some time already) neros buffer starts going down, followed by the devices buffer (though I dunno how much I trust neros accounting of the drive itselfs buffer). CPU usage is low (no spyware, adware or virueses on my comp). Ive even watched the task manager for a whole burn, nothing spiked above 50%.
Ive got a NEC 3500 with some RPC-1 firmware (think riplock removal as well) and a Lite-On SOHR-5239S. This seems to happen when burning DVDs on the NEC as well as CD's on the Lite-On.
Also when checking after a burn my NEC drive rarely gets above 2.4X... even on data dvds (just avi files or whatever).
I don't think this started once I upgraded my mobo from an asus a7n8x-dx 1.04 to an Abit NS7-S 2, but it did start not more than a month after (i did re-install windows XP in case your wondering).
Using nero 184.108.40.206