I RMA'ed my first 3770k through Intel's warranty center, it was about as expected.
Tech support wanted me to run through a few simple diagnostic checks just to make sure there wasn't anything silly going on (eliminate user-error in a non-insulting manner

) and after a day or two of very low frequency emails they gave me an RMA number and told me to send it in.
Naturally they are going to ask you if you (1) overclocked your processor or the ram, and (2) do you have an Intel performance tuning warranty.
If you have done (1) but do not have (2) then I recommend you go ahead and buy the warranty right now (costs maybe $20 for your 2500k) and then in 30 days you get a no questions asked "replace my processor please" opportunity from Intel.
They don't care if you bought the warranty after you killed your processor from overclocking, it has been checked and confirmed in a previous thread in these forums. Seems like it would be fraud but it isn't.