I've been tri-boxing on two computers for a month, and today I started two additional trial accounts to try five-boxing. I have my main on one computer, and the rest on another. The alts are on 800*600, no sound, all video settings on lowest possible.

The second pc is perfectly fine for two alts, but running four instances of WoW is a bit laggy. Or rather choppy video, and occasionally thrashing hard drive. I have only tried running around the starting area so far, and the lag didn't actually cause any problems, but I fear things will get worse when I get to more populated areas. I wonder if I can get by with an upgrade, or should I get a brand new computer? Or four new computers?

If upgrading, what parts should I focus on?

Mobo: ASUS A8N-E nForce4 Ultra
CPU: AMD Athlon 64 "venice" 3000+ (1800 MHz)
RAM: 2 Gb (4 * 512 Mb Corsair Value select)
Graphics: Club3D Nvidia GeForce 6600GT pci-express 128 Mb
Monitor settings: 1600*1200 pixels