FPS drops for 5-15 minutes after gaming for 1-2 hours

[opchooey]

My FPS stays consistent on all games for the first hour or two of gaming. After awhile, my fps will drop along with gpu and power usage. The fps will drop when turning in game otherwise its fine but its unplayable. After around 5-15 minutes it will return to normal. Temps stay at around 50-60 until turning in game then the temp drops to about 45 as well. What i dont understand is when i go to stress test my graphics card immediately after getting the drops, everything works fine.

Intel i7-7700k
GTX 1070
16 GB RAM
1920 x 1080 60Hz Monitor

 

[Lutfij]

CPU cooler+any overclocks:
Motherboard:
SSD/HDD:
PSU:
OS:

Game titles you've taxed the system with?

Are you on the latest GPU drivers courtesy of Nvidia? Have you tried uninstalling and reinstalling your GPU drivers?

 

[opchooey]

CPU cooler+any overclocks:
Motherboard:
SSD/HDD:
PSU:
OS:

Game titles you've taxed the system with?

Are you on the latest GPU drivers courtesy of Nvidia? Have you tried uninstalling and reinstalling your GPU drivers?

h100i v2 , gpu and cpu are superclocked
asus maximus ix hero
1 TB ssd
evga supernova 550 g3
windows 10(i do have the free version with "activate windows" watermark)
Playerunknown's battlegrounds and rocket league, cs go as well
i have latest drivers and have uninstalled and reinstalled
(i also tried switching card to different slot)