I'm using an MSI 645 Ultra with a 1.8a at 2.52g(18x140fsb).
I haven't had any reboot issues. I did have to do the wire trick to get the vcore up to 1.67. Without the wire trick the max I could get stable was 2.25g because at a vcore setting of 1.6v the actual vcore fluctuates between 1.53-1.56v.
I'm running the stock HSF and Crucial DDR at 350mhz(cas 2.5, normal timing to run at that speed)
Other than the low vcore settings available and questionable temperature readings I haven't had any problems. Not bad for $73 but the Epox 4SDA for $80 might be easier to overclock with.
Some benchmarks at 2.52 gig
Sandra 2002
memory scores....2547/2549
CPU multimedia...9933/12119
CPU arithmetic......4721 1502/3087
3Dmark2001se .....8283 (GeForce3 ti200 at 220/500)
BTW, I plan to back off to 2.4g(18x133fsb) because this is stable at real vcore of 1.60v and all the software I use is plenty fast at that speed. It's nice to know the extra speed is possible though.
Some benchmarks at 2.4 gig
Sandra 2002
memory scores....2447/2426
CPU multimedia...9456/11528
CPU arithmetic......4502 1430/2938
3Dmark2001se .....8090 (GeForce3 ti200 at 220/500)