My previous rig: a64 3000+ 754 newcastle, 2x256Mb crucial pc2100 ram, mobo Asus k8n w/ nvidia-250 chip. I oc CPU to 220 fsb x10 = 2.2 Ghz, ram to 148hz (ram:cpu = 2:3), which runs pretty stable, and passed prime95 on 12 hours mixed testing.
My current rig: only replaced the ram with one 512mb...