only the 2500k and the 2600k can be truly overclocked. the others have and dont quote me some kind of oc throttle control.
I have my 2500k oc to 4.5. it can easily do 4.9 with no problems, but I see no point going higher than 4.5. you may say, well I dont overclock, but those 20 bucks is good insurance for the future.
semp