Random brightness on-screen indicator sabotaging FPS in MGS Phantom Pain

The Problem:

While playing only Metal Gear Phantom Pain, the game's frame rates get destroyed by intermittent instances of the brightness indicator appearing on the screen.

I've found that this problem only occurs when the laptop is plugged in.

I've altered the power settings while gaming to benefit performance above all, even when unplugged. 100% brightness all the time, along with 100% processor speed, etc., etc...

When unplugged the problem disappears, however, after several moments, the fps drops and the color gets leached of dark blacks.

There is no change if I play in bright or dark environment. No change if I cover the sensors. No change when I disable Adaptive Brightness. No change when I disable sensor monitoring through admin system settings.

Does not occur at any other time, during any other usage. Games, heavy work loads, videos, nothing.

Windows is updated. Drivers are updated.

I have not re-downloaded the game. It doesn't seem to be a problem with the game, more a hardware problem.

The charger cable is new and seems to function perfectly normal.

Last but not least, sometimes the problem just goes away, but there is absolutely no rhyme or reason to it. There is no correlation to location, power outlet used, battery charge level, temperature, background applications running, game settings, system
settings, time, environmental lighting, game's brightness level, or me yelling and hitting things.

Seemingly minor problem, but it just saps all the fun out of the game. When it occurs, it occurs every 10 seconds or so. Or 20, or 30. Can figure it out. Please help!

:)

 

What Xbox One game are you most excited for?

Game available on XBO on or near launch day? Forza 5. Later on, MGS: The Phantom Pain should be amazing.

 

Metal Gear Solid: Ground Zeroes Deja Vu Mission Not Available

I have the same exact problem and I can't even transfer my data to MGS V Phantom Pain. So frustrating!