Your lucky although I didn't try it just on its own, but from the other comments in this thread its prolly best to change the voltage.
Yesterday is history, today is a gift, tomorrow is mystery.
It depends on the motherboard though.
MSI boards currently don't have a vcore option, you can either do auto vcore and the voltage will go down when the cpu goes idle with EIST and C1E, or you can set the vcore to what you want, but it won't go down even with EIST and C1E enabled.
On mine, I can either, set the vcore to 1.24(LLC will bring it to about 1.3) and it will never go lower than 1.24 or I can set to auto, and it will go anywhere from <1.0 to 1.31 depending on load.
I'm hoping MSI will change that soon....
And? You realize that the voltages being pushed through an i5 2500k (even on the high end at 1.5v or so) cause no strain when the CPU isn't under load. The wattage/amperage, and in turn the stress on the CPU, are much lower. Allowing your CPU to downclock to 1.6GHz, but keeping the voltage steady will not harm it at all. My vCore is set to 1.35v constantly, for instance. The lower vCore on the upper end (during load) will save you more power, heat, and stress on the CPU than allowing it to idle at lower voltages.
Also, allowing LLC to raise your vCore under load is typically considered a bad thing. With any LLC, your vCore will micro-spike when load comes or goes. If idle is 1.24v and load is 1.3v, then it will micro-spike higher than 1.3v during transition between idle and load.
(Since I'm kind of drunk, and may have missed this)
Question:
Have you ruled out BSODing from high-temps?
Are you using an aftermarket-cooler? Did you 'ruin' your thermal compound in any way? What does your airflow look like in your case? Have your run mem-test? If it only happens in games or similiar, have you made sure your six-pin/eight-pin connectors are securely connected to your GPU? Have you reseated your heatsink? Made sure your GPU is securely fitted (with the plastic clip clipped) into your PCI-e bracket?