Back in March of 2012 I built a system with the i5-2500K chip. This chip is known to be a superb overclocker, and I purchased a recommended heatsink (the Hyper 212 plus) and gave it a whirl. I decided it wasn't for me, primarily because of the extra fan noise. Using the stock fan, the system is almost totally silent and runs 4 cores at 3.3 Ghz (one core will go "turbo" to 3.7) and this is just fine for me.
Note that the Coolermaster Hyper 212+ is an amazing bargain at about $30 and outperforms many more expensive heat sinks. However, the smart control of the stock fans makes the system almost silent with stock speeds. Once you push speeds with the Hyper 212 the fans do have to get busy.
Now my son is building up a system and has an EVGA motherboard, brand new. It wouldn't be my choice of motherboards, but the price was right, a friend of his simply gave it to him. It does SATA-III (6G/s) and has USB-3.0 and looks like a nice board. Reviews complain that he CPU power section runs hot and that it only supports Sandy Bridge processors. But the relevance of all this is that my son and I have agreed that I will give him the i5-2500K and I will go shopping for another processor.
This will go into a machine running Windows 7 and with the primary purpose of running photographic software (primarily Lightroom, but also Xerene stacker, and other photo oriented tools). I have Lightroom 5, and people say that it does make use of multiple cores (it definitely uses all 4 cores on an i5). Rumors are foggy about whether it makes use of the additional 4 hyperthreads on an i7 processor.
My processor choices are the i5-3570K versus the i5-3770K. Prices for these are $320 versus $220, so the question is what the extra $100 will buy me. In short it will buy me 4 hyperthreads and a cache that is 8M in size rather than 6M.
I have always been a fan of stable and reliable systems and have scrupulously avoided overclocking. In all cases overclocking will cause the processor to run at higher temperatures, which can naturally be expected to be harder on the processor. On the other hand I have never had a processor fail on me (but of course I have never overclocked my processors).
The Ivy bridge chips tend to run hot as is, and I have read reports of people with stock coolers seeing temperatures over 70C even without overclocking -- so the only thing to do is to do some experiments if I want to try overclocking the 3770K. First check temperatures under load with the stock heat sink and go from there. The Hyper 212+ is widely recommended as an improved heat sink (the same one I decided not to use with my i5-2500K because of fan noise). People say it should be reasonable to push the clock to 4.5 with the Hyper 212. Certain people have overclocked to 4.0 with the stock heat sink and seen temperatures no higher than 70C under load, but the feeling is that they must be very lucky and gotten a particularly cooperative chip.