Sudden cpu speed drop while gaming

[Yolo-.]

Hi. So straight to the point here

 

I have a problem with my laptop.Its suddenly underclocked to 400mhz (0.40 Ghz) while gaming. I've checked the thermals i though its a thermal issue as usual but its stood 68-85C while gaming(before it happens), and i got immediately confused  since those numbers arent supposed to be high enough for laptop like these so, on a second though i though its a virus or something so i scanned my laptop and found nothing so, i did the usual stuff for things like this,update the bios,update driver,and etc still no avail. i changed my power plan to a balanced power plan it works,but i sacrifed to many performance and make my game's load slower. 

 

Heres my laptop specs:

 

Lenovo IdeaPad S340 14-API

Cpu: Ryzen 5 3500U

Ram: 8GB (2X4gb)

 

Things i did to fix the problem:

Updated BIOS to the recent version

Updated CPU drivers

Change power plan to balanced power plan

 

I hope you guys can help me fix this issue 

 

Thx for reading

 

 

[Neutraliz]

Hi.

Do that issue trigger stutters ? 

[Yolo-.]

yes