Whats wrong with my Sony NEC Optiarc AD-5170A?

Here is the benchmark test done with Nero CD-DVD Speed 4.7.0.2 (attached image)

General Information

Operating System Professional (6.00.6000 )
Drive Optiarc DVD RW AD-5170A
Firmware Version 1.O2
Serial Number
Disc DVD-R
MID PRINCO
Capacity 4.01 GB


Any help is appreciated

New benchmark, different media (much worse result here..):

General Information

Operating System Professional (6.00.6000 )
Drive Optiarc DVD RW AD-5170A
Firmware Version 1.O2
Serial Number
Disc DVD-R
MID TTH02
Capacity 1.14 GB

Log

Time Elapsed Action
[09:11:16] Starting transfer rate test
[09:17:37] 6:20 Speed:6-2 X P-CAV (9.31 X average)
[09:17:37] Starting access times test
[09:18:04] Random Access: 267 ms
[09:18:38] 1/3 Access: 343 ms
[09:19:20] 1:44 Full Access: 421 ms
[09:19:20] Starting CPU usage test
[09:19:36] CPU usage at 1X: 6 %
[09:19:53] CPU usage at 2X: 25 %
[09:20:20] CPU usage at 4X: n/a
[09:21:07] 1:47 CPU usage at 8X: n/a
[09:21:07] Starting burst rate test
[09:21:11] 0:04 Interface burst rate: 41 MB/sec (42003 KB/sec)
[09:21:11] Starting spin-up/down test
[09:21:15] Spin-up time: 3.21 seconds
[09:21:29] 0:18 Spin-down time: 3.45 seconds
[09:21:29] Starting load/eject test
[09:21:31] Eject time: 1.75 seconds
[09:21:49] Load time: 17.49 seconds
[09:21:49] 0:20 Recognition time: 0.08 seconds
[09:23:13] Starting transfer rate test
[09:49:25] Error - NO SEEK COMPLETE (030200)
[09:49:50] Starting transfer rate test
[09:50:17] Error - NO SEEK COMPLETE (030200)

Anything revealing?

Could this be a power supply thing? If so, does anyone know of a good tool to check it with?

I'm running Vista Ultimate, but its not related to this as the problems started before the upgrade.