It is not very good at all according to some reviews, it maybe because windows currently isn't optimised for all 8 cores but this is said to be fixed with Windows 8? not 100% sure on that but looking at this site suggests it really is a poor offering from AMD and their top of the range chip is not as good as the Intel i5 2500K, the Bulldozer is very power hungry too.
I will likely upgrade from an AMD 3200 64bit to an intel i5 2500K or hold out for Ivy bridge within 6 months if it isn't too expensive.
http://www.techspot.com/review/452-a...dozer-fx-cpus/