Is my cpu bottlenecking my gpu?

There's no bottle neck at all. They're both entry-level products. The GTS 250 is entry-level for gaming. I think they go perfectly with each other, but don't expect your system to be a beast. If you want to play demanding games or get better frame rates, start with with GPU. The GPU dominates the CPU in gaming, because it's a parallel processor. It was designed specifically to operate on multiple pieces of data at one, and not necessarily to be fast. Think about all the matrix math that happens in a game. You could install a Core i5 750 and the increase in gaming performance wouldn't be impressive at all. Then, you'd have a bottleneck. If you want OC the video card, by all means go ahead, but ask yourself "Is a meager performance gain worth the extra heat dissipation?"