Question Fps Drops Stutters or i don't know how to describe.

[dinner]

So i've build a new pc :
Processor : Amd Ryzen 5 3600 6/12
Rams - Viper Steel 3600MHz
PSU - 650w deepcool from a tierlist.
CPU COOLER - Stock from amd for now.
Motherboard - Asus Prime B450M-K II
GPU - GTX 1070(used)
Monitor - Asus Viewsonic VX2458-C-MHd 144HZ

So i don't know sometimes when i do play valorant, i get 144FPS Capped and it doesn't drops but still i got lags when enemies appear like it will show 144fps but still lag sometimes it drops to 137~
Tried many tweaks on internet over a youtube but nothing helps.
Any help will be appreaciated

 

[Lutfij]

PSU - 650w deepcool from a tierlist.
Exact model of the unit?

 

[dinner]

DQ650-M-V2L