So I fiddled with my system a little more.
I think I've arrived at my final stats:
2505mhz CPU (140% overclock. not too shabby.)
228mhz DDR (so really 456mhz) RAM
Stress tested it for 10 hours today without a single error.
Only thing left to do is tighten up the RAM timings as much as possible.
oh, and reinstall a few 10's of gigs of software. ^_^