I know the i5 3570k is obviously better compared to the 2500k when both at stock but, I will be slightly overclocking.
And i know that the 3570k has higher temps when OCing but will it still be better then the 2500k at say 0.5Ghz difference?
I will be using a Thermaltake Frio cpu cooler and arctic silver 5 thermal compound on a z77 Sabertooth mobo.
Rig used mainly for gaming (Will be using EVGA GTX 670 FTW so will not be using onboard graphics)
Yeah go Ivy Bridge. I moved from an i5 2500K to the 3570K and to be honest I did not notice a difference in day to day use but I did notice a gain in video encoding. I also slightly overclocked my 3570K to around 4 ghz (corsair H100 water cooler) with no temp gains. Also, Do not forget the 3570K enables PCIe 3.0 for your Geforce 670 (which I have one of those as well).
The Intel® Core™ i5-3570K is about 6% faster then the Intel Core i5-2500K at the same speed. If you were to overclock the Intel Core i5-3570K to 4.3GHz and the Intel Core i5-2500K you would have about the same level of performance from both of them.
Most people are finding that they can get up over 4GHz without changing the voltage at all (Which is where the big temperature increases come from). So I would go with the Intel Core i5-3570K over the Intel Core i5-2500K.