Will this graphics card do what I need? Is it compatible?

I'm just wondering if this graphics card will be compatible with the Dell Optiplex GX 620 (Large case). All I want it to do is play league of legends and basically nothing else, maybe minecraft on the side. On low settings without the graphics card I get 25+ FPS but I want it to be better.

Added (1). http://www.amazon.com/...004X6ABTM/

Guest

It's not about the case, it's about the motherboard. If possible, can you list your budget? I'm pretty sure it's possible to build a low-budget PC that will run LoL and Minecraft on 60fps high settings.

ImFrostii