Hello,
I decided to upgrade one of my machines form an Athlon X2 4000+ to a Athlon II X4 640.  My BIOS version is 12a, and according to the supported CPU list this should work.  As soon as I swap the CPU in however, I get continuous long beeps.  The manual indicates this is a graphics card problem.  I use the onboard graphics card, the system has 4GB in 2 DDR2 sticks.  I don't overclock, I don't remember what speed the memory is but it's not any kind of crazy fast stuff.
When I put the original X2 back in, it's fine.  Any suggestions as to how I can get this working? 
Thanks!