Well, let's scrutinize this more anal-retentively.
I am relatively new to over-clocking, in comparison to the number of year's I've been building and modding computers. I taught "Computer Architecture" and "Assembly Language" frequently over some six years during the late 1980s through the mid-1990s, but I was always a "software" person. I'm not an electrical or electronic engineer.
Personally, I've discovered that with the right choices of components, you can achieve fairly satisfactory over-clocks without changing the CPU VCORE beyond its default or "Auto" setting. So there's a range in which you are within the warranty of the processor on its voltage setting and actually right at the "stock" voltage.
Beyond that, there is a range of voltage settings that may be within the processors "warranty" range, but you also notice a slight increase in processor temperature -- maybe the idle temperature increases by 1 or 2F at a controlled room-ambient, and the load temperature also increases proportionately -- by the same amount.
It is said that heat and voltage are the primary, most significant enemies of processor longevity.
Also, I am wondering if a slight voltage increase may have a two-way influence on temperature: that is, by raising the voltage slightly, there are reasons which cause temperature to decline slightly, and reasons for which it might increase slightly. For instance, I found that load temperature was higher at the same room ambient at a lower voltage setting and the same external frequency (FSB) setting, than at a slightly higher voltage setting and the same external frequency when running PRIME95 "Large FFT, stress with heat."
So the question is this. If the warranty limit of the processor is 1.55V, if the "stock" setting seems to produce voltages at or below 1.5V, and that "idle" voltage even under "stock" settings seems a few hundredths higher in BIOS and climbing toward 1.58 or 1.6V in the OS while "load" seems to depress the value toward or below 1.5V in the OS, how much does it affect processor longevity and performance to bump up the VCORE to 1.525V if the peak values (at idle) don't significantly vary from the peak values under the stock setting?