CPU or GPU holding my system back

[Aveach]

I'm starting to not be able to run games on even high anymore so I figure it's time to replace some hardware.

CPU: Intel Core i7-2600 CPU @ 3.40 GHz (8 CPUs), ~ 3.4GHz
GPU: NVIDIA GeForce GTX 560 Ti

Which one of these is bottle-necking the other? Do you have any suggestions on what I should replace one of these with?

 

[Lmah]

The 560ti is holding you back, it's a bit dated. I would wait to see what nVidia announces this month before upgrading, you may be able to get a good deal on say a GTX970, also the GTX770's prices are going to be cut down as well if that fits your budget better.

 

[sincreator]

Yup the GPU is what is holding you back. Once the bottleneck shifts to your CPU, you can always look at overclocking it. The i5 Sandy bridge chips overclock very well, and still compete very well against ivy bridge, and haswell.