For the last few months or so i have had Fps drops in all games i play. i have had 3 different graphics cards and i experienced same FPS drops. Most games i play include dota2/diablo3/skyrim i seem to get a constant solid fps at 120 or 70 or 80 depending on what game and settings but nothing i seem to try has stopped these fps drops. In dota i can play for a few mins at 120 fps then my fps will divebomb to about 20-30 for around 10 seconds and then return to 120 fps. I have applied new paste and even fit a new fan but my temps seem to read find when these spikes happen and im out of ideas. i have changed power settings that other threads have suggested and reformatted and defrag countless times. this was taken from opening the game, playing for a few moments and experiencing a few fps drops then coming out of the game to take the screenshot.
it feels like theres something wrong with your vsync.try modding the settings in your nvidia control panel under manage 3d settings vsync.Maybe setting it to adaptive might help you.
looking at the fluctuating GPU usage (it's waiting for data), there seems to be a bottleneck in some other part of your PC. How's that CPU doing?