so i have a radeon hd 7790 1gb @ 1075 MHz, and recently i have been playing bf4 beta. i tried to overclock my gpu to 1200MHz (which is the max) i turn up the fans to 75%, which is more than enough to keep it below 40 degreess C. i also put up the power draw to +20%. but for some reason my game will suddenly get this huge lag out of nowhere. someone told me it was because of the card not having enough power, but i have a 650Watt psu, which is more than enough for my system, plus, i put on the +20% power draw thing on in CCC. why is it doing this?