I want to overclock my i52500k to 4.5Ghz if possible, and of course I want the best performance and stability.
I want all my games to run super smooth lol, no stuttering plz.
I don't plan to use CF/SLI in the future.
the 2500k is now obsolete and is replaced by the i5 3570k
While it is technically replaced by the 3570k, the 2500k is by no means obsolete. It's not even obsolescent; it's a fully viable choice of CPU. Both the 2500k and the 3570k will become obsolete at the same time: When the new LGA 1150 CPU socket is introduced.
The 2500k is somewhat slower than the 3570k, but overclocks better and is cheaper.
OCing better doesn't automatically mean it is better. Ivy bridge has a better clock to clock ratio and is faster per clock.
I didn't say it was better. It isn't better, but it's cheaper. Cheaper and only slightly less performance = at least as much performance per dollar/pound, if not more. If you don't believe me, then check out Tom's Hardware's own guide; it recommends the 2500k but not the 3570k.
I did, but it doesn't change things on its own. Especially when Ivy Bridge costs more and gets hotter when overclocked. As I said before: Tom's Hardware actually recommends the 2500k and not the 3570k. That doesn't say "2500k is obsolete and should be avoided" to me.