For explaining this, we need to discuss to point:-
1. Gaming at 1080P or higher resolution: Here most of the Graphics intensive games become more GPU dependent than CPU. So a good CPU and a better Graphics card combination is the best choice if you have budget constraints. There is no doubt, i5 3570K is a very good gaming CPU but it costs almost 14K in India and a good motherboard for overclocking will cost you around 12K. Now if you go with a FX-8350 @ 11.5K and a 9K 990FX based motherboard, with the saved money, you can actually upgrade your card to a HD 7970 from a HD 7950. Now at 1080P resolution, FX-8350 + HD 7970 combination will do better than a i5 3570K + HD 7950/ GTX 670 combination, at least with 95% of the games.
2. Multi Core Optimization: This is one feature all the gamings are hoping for long time. Battlefield Bad Company 2 is the 1st game to use all the 4 cores of a Quad Core Processor, although not optimally. Crysis 2 and Battlefield 3 are the 1st two games to use almost 8 threads. But with the recent developing like Crysis 3, Far Cry 3 are couple of example of games which have very good Multi-Core optimization. In fact in Crysis 3, FX-8350, which used to considered as not so good gaming CPU compared to i5 3570K, actually competing with i7 3770K at 1080P resolution. Even the low end A10-5800K, A10-5600K are actually beating the i3 3220 by a good margin.
If you look at the different review sites, specially Tomshardware, they have started to recommend quad core chips in their value builds instead of Intel Dual Core Processors.
So, in my opinion, going by the current trend, if you opt for a FX-8350 then you will get best of the both world, with the saved money, you can get a more powerful GPU and, for future gaming, you are getting a powerful Multi-Core CPU.