I have a Philips DVR1648P1 P2.2 and when I try to do a Disc Quality check with Nero CD-DVD Speed it goes very slow, < 1x. Is this normal for this drive ?
Philips DVDRW's doesn't support Disc Quality scanning with Nero CD-DVD Speed. The scanspeed is slow (as already pointed out by you) and PIF's are not displayed.
On the other hand BenQ equivalent (DW1640) does support this function.