Hi
i have the same problem with my pc :
Prozessor: AMD Ryzen 3 3200G (APU)
Mainboard: GIGABYTE B450M S2H
Grafikkarte: AMD Radeon RX Vega 8 (iGPU)
Arbeitsspeicher: adata d60g 2*8GB (3000MHz)
Festplatte: Team Group T2535T240G 240GB SSD
* Install AMD High Performance Power Plan For Gaming.
1 * Check your BIOS version and update from GIGABYTE (make sure and pay attention to choose the correct BIOS).
2 * install amd b450 chipset driver from amd not from GIGABYTE :
https://drivers.amd.com/drivers/AMD_Chipset_Software_win10_2.17.25.506.exe
3 * install amd radeon software for AMD Ryzen 5 3400G:
https://drivers.amd.com/drivers/non-whql-radeon-software-adrenalin-2020-21.5.2-win10-64bit-may17.exe
4 * update RGB Fusion software or uninstall it if you don't have rgb ram :
https://download.gigabyte.com/FileList/Utility/RGB_Fusion_B21.0520.1.zip
5*uninstall easytune and easytuneengineservice.
6* windows 10 update.
7* max ram frequency supported for Ryzen 5 3400G 3000mhz.
8* update Realtek HD audio driver from GIGABYTE.
9* change your ssd sata cable, (use sata cable that came with motherboard).
10* 1 * switch ram slots, (change ram slots), (change ram location ).
2 * try with ram1 and try with ram2 if you have 2 ram.
3* i think 2*8gb ram better than one ram 1*16gb
11* if you have new 650w power supply try it
"To meet expansion requirements, it is recommended that a power supply that can withstand high power consumption be used (500W or greater)."
Check page 13
https://download.gigabyte.com/FileList/Manual/mb_manual_b450m-s2h_e_1101.pdf.
10* enjoy your pc.
l have make all this 11 solution in one time i don't know which one is the problem,
but i have a doubt in my psu thermaltake 450w change it with thermaltake 650w