Trying to burn 4 different dvd's at one time, what's best upgrade?

SPECIFICATIONS:


Motherboard: P5K-E
Ram: PQI 2Gb DDR2 800MHz
CPU: Core2Quad 2.6Ghz
Hard Disk: 1 Terabyte Western Digital Caviar WD10EACS
Optical: FOUR Asus DVD-Roms on Sata
PSU: 1000Watt Cooler Master Real Power
Graphic Card: Asus 7300GT Silent
OS: Windows XP Pro 32-bit

I'm trying to burn four different dvds at the same time with the specified configuration, but everytime I get them to burn, the speed drops at 1x-2x on all of the four dvd-roms. What do you think would help to speed up the burning proccess:

1. Change OS to XP/Vista 64-bit or Linux 64-bit
2. Change Hard Disk to Western Digital RAPTOR(much faster than normal disks)
3. Add another 1 Terabyte Western Digital Caviar WD10EACS and connect both in RAID
4. Something else (please specify what and why)

Thank You