I bought a DRU510A writer a few days ago and I have not been able to get it to write at 4x. I am using Nero 6 Ultra, and when I do a speed test before writing it tells me my data source isn't fast enough. This can't be correct. My system specs follow:

Asus A7N8X Deluxe Rev.2
AMD Athlon XP 3000 Barton 400Mhz FSB
1 Gig (2x512) Crucial 3200 DDR RAM
PNY Geforce4 TI 4400
Maxtor 80GB 7200RPM 8MB HD
Western Digital 60GB 7200RPM HD
Plextor 52x24x52 CD-RW
Win2K

I have the Sony set to master on the secondary IDE. I have it set to us DMA. I have updated the firmware to 1.0d. I keep Win2k updated. I disabled my Norton antivirus.

What could the problem be?