hello i have nvidia gt 640 gainward 1gb gpu and its pretty fine until today when i brought dayz now i could stream minecraft and cod4 and play at the same time with no lag or problems but when i play dayz its fine but when i livestream dayZ it lags abit and i got a tool that came with my gpu called EXPERTool where can i overclock my gpu now i want to overclock i little bit i dont want to make my gpu die i want it to last long but i want to overclock it a little bit so i can stream and play dayz at the same time do you think its safe and how much should i overclock it?