I would at least look at spending a few buck more and getting 16GB ram. Not that you need it all but that APU uses system ram to run. It's like a GPU having on board memory. The APU doesn't so it has to use the system memory to function. That way your system still has at least 8GB and the APU has enough to function.
Just what I have heard.
you're swaying me towards other things
Are you getting the GPU right away and crossfiring?