i5 2500k Overclocking
 

I followed this guide: P67 Sandy Bridge Overclocking Guide For Beginners but when I stress test with Prime95, after a bit, it always says something along the lines of Prem95 having an error and needing to close. I followed his exact instructions for 4GHZ except I pumped voltage up to 1.15

Not every chip is the same.. also that guide is using a 2600k, up your vcore to 1.2

Aight thanks!

Edit: Also, what's the highest safe voltage for these Sandy Bridge chips? I really want to hit 4.5 GHz.

You have an Asus board right? Try the auto-oc. It took my 2600k to 4.5Ghz with no problems.

Hm, I'll give that a shot. Thanks!

1.52 is the max voltage, you are in my opinion perfectly safe under 1.4 as long as you cool it properly, nothing wrong with running over 1.4 either :P

NO to auto oc, change voltage to 1.35v for 4.5ghz, ~1.25v for 4.2ghz

Maybe. Maybe not. Not all chips are the same.

Auto OC will work for the OP's specific hardware, which makes it a decent starting point.

I forget what it's called, but the auto o/c on the dumbed down first bios screen took me to 4.4 no issues.

I know not all chips are the same, but it is the recommended voltage to start off with on the 2500k, I've built a few computers for my friends with 2500k, and got it up to 4.5ghz with 1.35ghz. Of course I would run prime and check if its enough voltage, some chips can run 4.5 at only 1.25ghz, but for most chips 1.35 is the best voltage to start with. The turboevo utility also overclocks baseclock and overvolts, so I would recommend doing it manually, there are plenty of forums online with the speed people are running their 2500k at and the voltage, so you can get an idea the amount of voltage required.