I'm running Oblivion with all the expansions/DLC packs installed on Q6600 (Core2Quad - 2.4ghz) with a Radeon HD3870 on a 1920x1200 resolution 24" monitor and it runs fine with everything up full. The only thing is because of some weird bug or something it won't let me enable AA and HDR at the same time. If I want AntiAliasing I have to have 'Bloom', if I have HDR I can't have AA.
So I think you should be completely fine.
Oh and 3D Guru seems to suggest that a Phenom II will go into that boardhttp://www.guru3d.com/article/msi-785gme65-motherboard-review-test/