I had the same exact issue when installed a GTX 675m into my 1761 (Same processor as you). Sadly, I think the problem relates to the power consumption of the card. I know the internet says that the 770m has a power consumption of 75W (same as the 570m), but I don't think that is the exact power consumption and that there might be a small difference between cards. That's just my guess. Try lowering your screen brightness, unplugging unnecessary cords, etc. . In my case, turning down the fan reduced the drops in FPS. The drops were still there, but less frequent which led me to believe that reducing the fan's power consumption allowed more to be allotted to the card. So the question is: Is there any way to increase the core voltage or edit the power flow even though the Aptio bios is kinda crap? Maybe the unlocked bios allows for that...I don't know. Also, my Clevo 770m arrives tomorrow, so we'll see if the same thing happens to me.