You would be surprised, mate. FX4300 is SLOWER than the old Phenom (and even Athlon) X4s clock-for-clock. You need to overclock it to 4 GHz or above get the performance on par. We have several of them in our company, and they were supposed to be an upgrade, when in fact they were a downgrade. This architecture really sucks.
The only CPU in this line that seems to be a solid upgrade over 6-7 years old CPUs is FX6300. No less.