That is not a "light gamer", that's a serious gaming machine that has only one apparent issue... you've got an entry level PSU in a very high quality build. The PSU is not the place to cut your budget, I'll recommend a very high quality PSU (you'll pay for it but...) for that build like the Corsair AX or HX models, the SeaSonic G or X series models or other highly rated unit more fitting to the quality of the build