So i should just get another card if the frames are so little of a difference. I have a fx4100. I know it's not exactly a good cpu, but unless I'm playing a very intensive cpu game I should be fine right. And I am not interested in upgrading to another amd cpu.
Personally, staying in the same budget, I'd get an fx8320, 1 7950, and a SSD. I think you'll hit the point of diminishing returns quickly with the vidcards and your processor. If you decide in the future that one 7950 isn't enough you'll know you have the pieces in place to utilize their full potential.
Take the 4100 and make a nice HTPC or sell it. It's not a bad processor but you're talking about a rather high end video card so you need to address the potential bottlenecks. I'm always of the opinion a well rounded machine is far more enjoyable, and you'll have 8 cores to tackle any heavy compute tasks. (Encoding Rendering, etc....)
I don't know what resolution you're planning on gaming at. The 7950 is going to be really fast unless you go really high res. I run a single 6950 for 5040 x 1050. I have to turn down the details a bit, but still seems fast and eyefinity is awesome. I thought I was going to want to purchase a second 6950, gotta say I'm plenty happy with the performance of the single card.