So I'm wanting to upgrade the graphics card in my x51 r1. I know that you have to stay within the confines of the systems size and power limitations. Here is what I have: i7 3770, 16GB Ram, GTX 660, and the 330W PSU. If anyone could possibly provide a list of compatible graphics cards, that would be amazing. AMD or nVidia, I am not partial to either but do somewhat prefer nVidia. Thank you in advance!