1.5v? Are you nuts dude I got an E2140.. 375x8 giving 3000MHz, at 1.35v!
1.4375v for a 100% OC, lower that to be honest.. it should be 100% stable at 1.35v if not lower.
Also, no need to up the RAM voltages if you're on a 1:1 FSB
RAM divider, it will be running below stock if you're on DDR2-800, it will be running at 750MHz so no need to up your volts!
FSB overvoltage.. leave that as low as it can be (in my case) and it is 100% stable.. over 10 hours of Stress Prime 95.. so I think my point is proven. Not all voltages have to be raised, they only have to be raised when and where neccessary!