@ Boon888: You say your CPU is getting to 69 to 75 degrees, if that's centigrade that's your problem, the CPU is getting FAR too hot and you need to something about it URGENTLY.
Think I know what you mean with FC3 and there is a fix, which may work with Prototype2 as well which is to cap the framerate.
Before you start, load up the game, set it to the 'high' preset and disable the vsync options, also disable vsync in the drivers.
Download and install Radeonpro.
Start it and click on the 'profile' button to highlight it then the little green cross in the top bar to open a new profile.
Navigate to the game executable (the DX11 one) and select it then go to the 'tweaks' tab.
There click the 'dynamic frame control' box and set the framerate to about 45 to start with, no need to save, the profile will be applied automatically every time the game is started. Note, if the game dips below the capped framerate the stuttering will return and I selected 45 FPS just because that number works for my rig, yours may be able to run at a higher number.
The game MAY seem to crash on startup, don't worry, just wait a few seconds and close the Uplay window that appears then click on the start button in the main FC3 screen that was behind it-my Steam copy no longer does this BTW.
You can edit the Radeonpro profile just by opening the program, changes are saved/applied automatically. It also has a number of other very useful features, but I'll let you discover them for yourself
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There will be a dropoff in busy villages/outposts.
Lowering alpha to coverage can also help and I don't play with AA enabled, on a 22" 1080 screen the general visual improvement is not, to me, worth the framerate cost.