Originally Posted by CynicalUnicorn
If you do go with an AMD octacore, you'll need a decent motherboard that can handle the power draw. However, they get ridiculously hot and you'll probably be limited by the cooler. At that price and especially form-factor, I'd go with Intel if you want decent overclocking that won't burn your house down or require liquid cooling. However, since console games will soon be taking advantage of octacore processors, Intel may soon be limited and hyperthreading just doesn't compare to more physical cores.
Crysis, I don't know about. But I believe it has decent multi-threading support. Battlefield is getting good with multi-threading. CoD just sucks on PC. As long as you watch out for AA and MSAA, you should be fine with anything at 1080p.
What's your budget? That's most important since AMD is best for low-end builds, Intel best for high-end, and medium-end all depends on budget and what you need. If you're willing to spend, for a CPU mobo combo:
$150ish - I'd go with a 6300, a medium to high end motherboard, and overclock as much as possible. 4.6GHz using basically your cooler gets socket temperatures below 63 degrees and core temperatures below 53 in my experience.
$200ish - Spend a bit more and get an 8320 or a better cooler and 6350 and go for 5GHz. Intel won't be good enough for the price just yet.
$250ish - This is where it gets complicated. An 8350 would fit in here, but AMD has crappy support for good AM3+ mATX motherboards. Plus, you're outputting all of that heat into a relatively small case. Intel seems like a better option for longevity, but you can get only a cheap motherboard for $75 since the cheapest Haswell i5 is $175. Stay away from the i3s - they're dual-core and AMD dominates in comparison.
$300+ - Go Intel. No competition.