Anandtech has a new article benchmarking a range of Intel processors - they say a future article will cover the AMD processors.
The article is meaty and will take a lot of time to digest, but the big take-home is something that I've always advocated, namely that the quad-core i5-series process is at least equal to the quad-core, hyper-threading i7 range, but you save $100 in price that you can put towards other use.
Surprisingly enough, for all but the most extreme gaming with more than 3 GPUs, the extreme series of processors also show no or little advantage over the humble i5-range, with even larger price savings.
Of course, there are other things, such as video and graphics processing that may be more memory intensive, and may have an influence on buying decisions, but for the vast majority of gamers out there, this may be reassuring news. Of course, this is logical, since if games were designed for only the highest -end PCs, then the market for these games would be much, much smaller. But it also means the savvy gamer can have a competitive rig for around $1,500.
This is a messy graph, but it links to the full article which is definitely worth a read.
(http://images.anandtech.com/doci/7189/46704770.png) (http://www.anandtech.com/show/7189/choosing-a-gaming-cpu-september-2013/10)