Question Sudden performance drops after playing for a bit

[Hichoow]

I am using the Lenovo Legion Y520 15-iKBM.

Specs:
CPU: Intel Core i7 7700HQ @ 2.80GHz Kaby Lake 14nm Technology
Ram: 16GB
GPU: GTX1060 with Max-Q design

Basically what happens is that after like 30 minutes, my CPU suddenly uses less wattage. After this the temperature of my cpu and my fps drop.

Picture before the drop:

https://imgur.com/JXEYuEa

View: https://imgur.com/JXEYuEa

Picture after the drop:

https://imgur.com/dSXuelq

View: https://imgur.com/dSXuelq


I ordered a new adapter and that's coming in tomorrow. Is there maybe anything else that has to be done?

 

[TheNightTerror]

Can you tell if your CPU is underclocking itself for an unclear reason?

 

[Hichoow]

Can you tell if your CPU is underclocking itself for an unclear reason?

How do i check?

 

[DerpVed]

Temperature went up to 72 Celsius. That might be the CPU throttling to protect itself.