CPU Help.?

Do you have your motherboard yet? If not you may want to consider Intel, their motherboards are cheaper than AMD and you can get a lot more speed with an Intel CPU.

If you already have an AM3+ motherboard, AMD has two recent FX cores, the x300 and the x350. The x350 cores are slightly faster, but not a lot.

The first number simply says how many cores there are So an 8350 has eight 350 cores. Most programs won't use more than 4 cores.

You compare CPU speed with benchmarks, like Passmark or CPU Boss.

AMD's best chip is the 8350, but the single core benchmark score for the 8350 is only 6% than the 4300.
The 4350 is 6.5% faster per core than the 4300.

The 6350 is a good middle ground, two extra cores to run background tasks while having slightly faster cores than the 8350.

the best cpu for you to upgrade too would be the 8320

The good news is that the FX4300 still uses an AM3+ socket, so you can use any modern AMD chip.

I'd recommend an FX-8350, I use one at current and it's a beast for its price of about £130.