The FX-9370 and FX-9590, as you may remember, run at 4.4GHz and 4.7 GHz base clock respectively. They can also boost up their clock frequencies to 4.7GHz and 5GHz. Both the chips house 16MB of L3 cache and have unlocked cores, making them a beast for overclocking; if you can handle the heat.
To use the CPU on your system, you should meet the minimum requirements specified by AMD, and they're not light:
~ 990FX/SB950 Chipset
~ At least DDR3-1600MHz memory chip
~ A 1200 Watt power supply for these power hungry chips
AMD has also recommended users to use either a Corsair H80i, Antec Kuhler H2O 920 or the Coolit ECO-II 120FB-Fat Boy liquid cooling system - if the 220W TDP didn't tip you off, these monsters make a lot of heat.
If you want to have one of these beastly cores, then you will need to spend a fair bit of your paycheck. The FX-9370 is listed at $319 on TigerDirect, while the 5GHz FX-9590 costs $829 to own. The expenditures don't end here though, as you will need a very high power PSU as well as a good liquid cooling system to get the most of your CPU. You could also pick up a pre-built system if you like, but expect the total price to be around $2000 or higher.