My first overclocking was on Pentium Celeron processor which was rated @ 800Mhz and i ran XP 32 bit with 256MB Ram, my mobo supported overclocking and i overclocked it to 1.2GHZ, but sadly whenever i overclock, i could run my system very fast at that time. But there was no-sound output at all.
Then, my next overclocking was Core 2 Duo E7200 from 2.53GHZ to 3.1GHZ Stable. at 3.2 it wasn't stable, no options to alter voltage.
and now, i m planning to get Z68 mobo @ overclock my current CPU to nearly 4.2GHZ and GPU to nearly Core clock speed -1GHZ with my new Arctic cooler =p