PC makes Buzz sounds every now and then

I've just built a Ryzen pc and everything went fine, except for a little problem. When opening a new browser window or having a huge battle scene in LoL the pc makes weird Buzz sounds 1-2 seconds and then it's gone. Happens more then once a day. PC doesn't turn off, screen doesn't freeze, nothing happens. Just the weird sounds.
Anybody know what it could be?

System:
Thermaltake core p3
msi tomahawk b350 board
Thermaltake 700w psu
Ryzen 5 1600x stock
strix Gtx 960 4gb
16 GB ddr4 Corsair rgb Ram 3000 mhz
cooler master Master liquid 240 waku
2TB hdd
240 GB samsung M.2 SSD

Could be your Fans. Maybe they start Spinning when you Start a process. You can avoid this by setting your lowest fanspeed a Bit higher

mfg