Depends on the games and how you use the rig, if you typically have apps open then more DRAM can improve loading times as more is available, it can also cut down on reads/writes to the page file, many games these days use more DRAM then what you have so obviously would help there. I would however suggest getting a 8GB set of DRAM rather than try and 'add' more DRAM, there are no guaranties that mixing different packages of DRAM will even play together (even another of the same exact model)