I kind of know what you mean here. I think I may have reached the end of the AMD road myself so to speak unless they come out with an improvement for the desktop market. It's a shame since I've only used AMD when they first introduced the 64-bit processor a long time ago.
Given the CPU support of your board, you might look at this, but I really don't know what kind of performance improvement you can expect.
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz Socket AM3 125W Quad-Core Processor HDZ965FBGMBOX
Even if you could find a Phenom II X6, I don't see where your board supports it.
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