The 3rd generation Intel® Core™ processors are running about 6% better at the same clock speed as the 2nd generation Intel Core processors. On top of that very few games will use the extra threads that the Intel Core i7 processors offer and the 2MB difference in cache really doesn't come into play. In the end it all comes down to the Intel Core i5-3470 bring the same to the table for less.
For gaming? Out of the two, the 3470 has better single core performance on top of being a newer architecture. I would recommend you get that i5 *for gaming.
this is partially correct and incorrect!
you are correct if he doesnt overclock but if he did then the 2600k would be well ahead. And SOME games DO take advantage of more then 4 threads and take advantage of overclocked intel cpus. the main and most popular game would be BF3 MULTIPLAYER. i show 50-60% usage across 4-8 threads constantly in 64 player servers.
just an fyi that his post is mostly correct but can be wrong.