The i5-2500K is an older processor but it is still very capable. I got mine overclocked to 4GHz very easily just by changing its multiplier. I tried pushing it to 4.5 but she wasn't having it. 4.3 seems to be the threshold of stability because sometimes the system will boot and sometimes it won't. I've kept power saving features on however because I like having it wind down to a lower clock when it is idle to save some power.

Overclocks like a champ at 1.3v 4.2Ghz

I absolutely love the i5 2500k with this Gigabyte GA-Z68X-UD3H-B3 motherboard. I don't really strain the OC too much, as it is only 4.1 GHz right now, with about 1.285 vcore. It still performs absolutely amazing in games, and haven't noticed any bottlenecking whatsoever.

slow but ok

For an old CPU, it performs exceptionally.

This chip is fantastic. Ran from 2011-2017 on a mild OC, and still going strong. I expect it will continue on for some time when I pass this system on.

This is a very solid CPU and one of the best overclocker I ever had, it runs at 4.6GHz with just 1.3 volt. I'm still happy with this CPU as of late 2016, hopefully next year AMD Zen will brings some healty competition in CPU market and price drops as I'm looking to do some upgrades in the upcoming months.

it can be overclocked to 4.5 stabaly

This CPU is..well.. there is no words for it. Maybe it is THE best CPU ever designed. Even today (2019) it still can run so many of the newer games (alas my GPUs are too old). I have it OC to 4.3 for some time now and the CPU just loves it.

It's a bit old now but it still works and is very stable