I have the setup you are thinking of getting, it works OK, not brilliant, just OK as far as I am concerned.... maybe things will improve over time as better BIOS support becomes available.
I got slightly better performance from the 6400+ than I do with the Phenom 9500.
If you are buying a new mobo, I would recommend that you get an AM2+ mobo, like the M3A series from ASUS for example.
Also I would consider getting the 9600 Black Edition which will be available before long, or wait for the newer Phenoms without the TLB errata which wil have different model no's like 9550 etc...
Good luck with your new build.
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