Is my I7 6700HQ throttle?

[coercitiv]

Edit: and after -50mv you should decrerase the voltage in steps of 10mv (so -50, -60, -70, etc.). When you will find the lowest value where your computer is stable, then you can save the profile.

Be weary of such "high" undervolts using offset setting, the voltage profiles for Intel's CPU also vary with temperature, and there's a certain undervolt threshold at which the CPU may be stable under load (high temps) but may not be stable under light loads (low temps). For some mobile CPUs that threshold could be as low as 50mV (even if CPU is stable with -100mV undervolt under load), and it's especially troublesome for beginners who see such recommendations on forums, since they encounter stability issues later.

My go to diagnosis for the problems the OP is having is GPU induced throttling - the GPU reaches a thermal limit (which is not max limit) at which, according to system settings, it will request CPU throttling to lower heat output and maintain high clocks. This is an old and known problem which appears on select notebooks that have poor cooling and power management profiles. (cooling may be good enough, but cooling configuration may be improper)

The sporadic nature of the FPS drops (first in the 3 mins, then later) may be explained by fan behavior. New fans tend to have a response curve, gradually increasing speed in order to avoid those annoying sudden RPM changes - sometimes they increase speed slower than temps rise. They may also have a speed profile configured in such a way that throttling occurs first instead of fan reaching max potential, which in turn prevents the fan from ever reaching max speed (since temps drop and fan profile stays bellow max forever). This is not theory, it's based on my own experience with a 4700HQ + 750M combo on a Asus "multimedia" laptop.

This is why I asked the OP to run the games with CPU set bellow 100% in power management, since this setting should keep his CPU at 2.6Ghz and effectively reduce CPU heat by ~half. However, the OP stated that this setting made all games performing badly, including WoW. This is very strange and cannot be explained by temps/throttling alone. In the worst case possible he would see similar behavior to stock settings, but definitely not continuous bad performance.