I have an Asus M4785G-M board and was thinking of changing out the Athlon II 630 to a Phenom II 955/965 BE.
The 630 runs at 2.8 GHz, is the extra cache and core speed worth the extra money? I am considering the same change as you, but I have an AMD 620 that runs at 2.6 ghz.
The 955 runs at 3.2 GHz Processor. Is it "really" worth around $125? All your going to be getting is about 400 mhz core speed, and extra cache.
While playing left 4 dead 2, my current AMD 620 runs about 75% across all 4 cores. I can not justify the cost until my current CPU has reached its end of life. Until its maxed out and performance starts to drop, only then will I replace it. But right now I average 75fps - 100fps in games.
Keep saving your money, and lets see what happens in the next few months.
My personal rule for upgrades, do not upgrade until you can double your speed. A gaming buddy of mine gave me that rule back in the late 1990s, and I think it has served me well.
If you have a quad core right now, do not upgrade until you can get a hexacore or octacore for a reasonable price.