Whats the best GPU my system can handle?

As the title says, I am wondering what the best GPU my system can handle is. Currently I have a 6950 in it.

My processor is a FX 4130 black edition. I only have 4gb of ram but and upgrading to 8gb next month.

Any help is appreciated, thanks.

It really depends on how CPU-bound the games you play are.

To be honest, the first generation FX series were really bad for gaming, even worse than the Phenom IIs. If possible, I'd upgrade to a Vishera CPU before upgrading your GPU, if possible. And the extra 4 GB of RAM will help as well. What motherboard do you have?

http://www.newegg.com/Product/Product.aspx?Item=N82E16813128565

This is the motherboard I have.

Your motherboard has a 4+1 power phase, so I'd recommend against an 8-core FX CPU, and maybe even a 6-core. You'd probably want to get a better motherboard before upgrading your CPU.

At any rate, when you're playing a game I'd look at whether your CPU or GPU is bottlenecking and go from there.

Yeah I don't know how to do that though. 

I'd say the 270x is quite a balanced card with the 4130. You could use a higher performing card, but a CPU bound game will probably diminish the performance of anything higher than a 270x. So you could use a higher performing card, but it wouldn't necessarily have the best cost-benefit.

Probably the easiest way is by changing the graphics settings on games you play. With your current settings, see how many frames per second you're getting. Then lower the graphics settings so it's less intensive on your GPU, and then loo at your frames per second in the same part of the game as before. If the frames per second are the same, your CPU is bottlenecking.

The system is balanced as it is and you don't really have a choice when it comes to upgrading,that motherboard can't handle an 8 core cpu,even a 6 core might struggle,and if you upgrade the gpu the cpu won't  be able to keep up with the gpu. I'd say you keep the system for now and save money,you can sell it later on and use the money you saved for new parts,keep the ram,psu,case,hdd and sell the cpu gpu and motherboard.

+1 to this. I have the same configuration, well I have an fx-4350 and have no issues with any games.

might need to know what kind of PSU you are running.

 I have a 600W

Yeah I was looking at getting a 270X