toledo 3800+ overclock limit ?

hi everyone I'm overclocking a x2 3800+ and so far managed to get it stable at 2.8ghz vcore 1.42 and mem 466 @ 2.82v but as soon a try to hit 3.0 it will fail after a while, hence i tired ubber upper voltajes like 1.63 and just run stable like 2 hour max before giving a bsd
so far i tryed bigger memory divider
more voltage to cpu, ram and chipset

here are my specs

cpu cooler cooler maser hypertx with nmb fan runing at 3200 rpm 52 cfm
stock northbrige coolerx2 3800+ toledo core
abit kn8
raid max 450 psu
evga 7600gts(with gt core )

 

I'd invest in a Quality PSU, raidmax is low end.
A Weak PSU can and will cause stability problems

2.8GHz maybe all your chip can give, thats about the limit for most x2 3800's, dont worry about using a divider for the memory because what matters most is the max CPU speed.

Cooling is very important too, keep your cpu under 50c
Air cooled, I wouldnt run the V core over 1.5v