I recently purchased an i5 2500k, and at stock voltage I was able to get to 4.2ghz. I have a hyper 212+ and the temps were around 60C at load. Do you think I should try increasing the voltage? Does that void the warranty? How much would I be able to raise the frequency while maintaining a safe operating temperature? What is a safe operating temperature?
1. Overclocking voids the warranty.
2. If you don't tell them you overclocked, they won't know, more than likely but there is a risk.
3. No one can tell you if you should increase your voltage or not unless you tell us what you currently have it at.
4. 85*C ? Are you kidding? I wouldn't go past 60*C but that's because I aim to be safe. Intel does not recommend exceeding 72.6*C
5. I'm not sure what the throttle point temperature is, but if you hit it, you will degrade performance
The warranty is void if operating outside of intel's publicly available specs. Damage caused by overclocking is not covered by the warranty. Since the cpu turned on and is operating fine, then really forget the warranty, if it stops working later it's not the cpus fault and is not covered by the warranty. Intel's states the tcase at 72C but most would say you are fine to 80C in stress testing as they present unrealistic workloads. (But personally I don't like going over intel's stated tcase.) The tjmax is 98C which is also the auto turn off temp but it doesn't mean that it's safe to go that high. Testing shows rapid degradation above 1.4v (vcore) but even tom's doesn't like to go above 1.35.
If you overclock the Intel® Core™ i5-2500K and that causes damage to the processor then yes it will void the warranty. Within the normal setting of the multiplier it would be hard to know that you overclocked the processor if you didn’t tell us you had. Within the normal range of the components on the system memory at DDR 3 1066/1333 1.5v ±5%, and the processor running at the stock speeds there should be no reason for technical support to question a warranty on a processor that was at normal specs. Of course if you have changed the vcore or core voltage that may be able to be seen at later time.
In the end remember that these processors are designed for years of hard usage and if you keep it cool it should last for a very long time.
72C at 95W is just intel's specced thermal profile. The chart/graph shows higher watt=higher temp so more volts means higher tcase but you're still going to want to be below max safe temps at what intel deems safe.