Phenom x4 9650 or Phenom II x3 720?

I recently bought a Radeon HD 4850, and I should say, the graphics look amazing. Huge difference over my old 8600GTS.
But I can't help but get a feeling that the CPU is being the bottleneck, especially when I play CoH and Crysis.
So, if I decide to upgrade my CPU from my old Phenom 8400, which will be better, Phenom x4 9650 or Phenom II x3 720?
I wanted to upgrade to something like the Phenom II x4 940, but the TDP supports only up to 95W, so I'm out of luck until I buy a new mobo.
So, of these two CPUs, which will be better value? Or should I just save my money and go for something bigger later?
Thanks in advance.