Dell Latitude E6520 can handle many games on pretty decent performances, most A+ grade games from ca 2007 - 2011 (E6520 was released 2011) era should run fine on medium/high settings like game footage listed below (Battlefield 3 - runs playable frame-rates on 640x480 resolution, Starcraft 2, Arkham origins - these last 2 games have no performance issues on medium/high graphics settings, performance killers like anti-aliasing and DirectX 11 should be always turned off)
Newer more resource demanding games will run but on very low frame rates even on lowest graphics quality. Example: Newest Arkham series game Arkham Knight witch was released this summer runs very poorly: 5-10 fps on lowest settings possible
