You're better off with 4th generation, it uses less energy for more performance, and its integrated graphics are better. Also, if you're worried about temperature, both run hot (compared to Sandy-Bridge).
Intel i5 3rd gen or 4th gen, which is best for gaming performance. I have a budget of $230. I personally like the i5 3570 (non k)
if you have a 3rd gen uvy bridge i5 CPU,its definitely not worth to go for has well as we dont see any significant improvement in haswell.IF you have a 1st gen CPU(Clarkedale or Havendale) or sandy bridge then you better upgrade to Haswell.For Gaming ivy bridge and haswell both are very nice players.4th gen basically decrease in power consumption,but temp in some benchmarks are very high.For the 4570k just check ou this video:http://
4670k pros- slightly higher IPC, slightly more efficient, and has a few more up-to-date instructions and features.
4670k cons- slightly lower thermal headroom for overclocking.