In games not a few seconds, drops FPS

All modern games for a few seconds sags fps, the interval is different. Looked in task Manager, the CPU drops the frequency in those few seconds (in the screenshot shown) , but even when I disabled in the BIOS, the reset frequency, the game will still frisat and the CPU runs at 3.3.Mhz.
Watched the CPU temperature during proseda in some games to 58 degrees, others at 65, so a problem hardly in it.
The power set on high performance.
There may be a problem in the motherboard?
Here is my iron:
Motherboard - ASRock 960GM-VGS3 FX motherboard
Percents - AMD FX - 8300 (3.3 MHz)
Graphics card - Radeon RX 460
RAM - 12 GB
Windows 10