Slow(1 1/2 hour) burn times with nero / copytoDVD etc

Help
Dont know what Ive done wrong, but since formatting my PC and reinstalling
all my burning software, both Nero 6 and CopytoDVD take a stupidly long time
to burn a disk, CD or DVD.
Hardware as follows:-
MSI KT4 Mobo
Barton XP2500+ CPU
512 Mb Crucial PC3200 Memory
80Gb 7200rpm ATA133 Maxtor Hard Drive
Pioneer 105 DVD writer
Lite on 52 speed CDRW
Both Drives on Ultra DMA mode 2 setting
Nero Aspi shows as installed
If I run a film through TMPGEnc DVD Author and let it use its built in
burning software, its back down to 15 to 20 minutes.
I would really like to get this working, as its driving me mad.
If its any help to pinpoint the problem, the buffer bar at the bottom of the
burn page on nero, flicks between about 20% and about 90%, staying at 20%
for about 10 seconds, and then popping back up to 90% for about 1 second
before returning to 20% ad infinitum.