I am experiencing substantial frame drops in the most demanding games, such as BF1 and ROTR. In BF1, I will be running the game at Ultra settings at 1440P and getting around 110 FPS. Then, the games drops down to 50-60 FPS and I stay there the rest of the day. I have checked everything I can think of:
 
- Temps for all components are fine
- Voltage for all components are fine
- No parked CPUs
- CPU not a bottleneck and never gets above 70% utilization
- I did notice the min and max clock speed on the GPU suggests that the card is not boosting
 
System specs:
 
- i7 4970k at 4.4ghz
- GTX 1080 SC
- 16GB Corsair Dominator
- Samsung 850 Pro SSD
 
What is most frustrating is the card handles these high end titles with ease, well over 100 FPS, then drops every time without any rampant trigger. I have tried the below:
 
- Uninstalled GeForce Experience
- Reset Nvidia control panel to default
- Uninstalled EVGA Precision
- Toggled DX12
- Togged borderless, windowed and fullscreen
- Monitored all system temps and verified no heat issue
- Cleaned registry
- Used EVGA precision to force boost (result was really solid 120 FPS then the same random drop to 50-60)
 
Any other suggestions would be greatly appreciated. I have invested so much in this rig and seeing what it can do then being forced to play with weak FPS is incredibly frustrating. 

Thank you for the reply. I already had windows set to high performance. I had global power set to maximum, but changed to the config you suggested. The pattern still exists. The first run of the game gets 120 or so FPS for awhile then tanks to 50-60. Remaining plays until restart are the same. 

I had the same problems with BF1, I updated to latest drivers and set to maximum performance in 3D settings and it solved my issue.

Post a full hardware monitor graph from msi afterburner before & after the issue happens.