My games run slowly

[anas.angel55]

Hey
My pc specs:
CPU: core i3 8300
GPU: Asus gtx 1060 3GB
Ram: fury x (1*8) gb 2400
M.B: Gigabyte h310m

The problem is
Today i was playing fortnite smoothly at 120-140 fps then i exit the game and after 30 mins i back to play it
I got high fps drops be 120 fps then it goes to 15 fps then back to 120
I played 5 matches and it was the same
Why this happening?!
Another question
i have watch dogs 2 i got huge fps drops When i playing it
Also in low settings
i can't play the game
How to fix it ?
And thaanks
P.S : i newly built this pc
Thanks again

 

[anas.angel55]

Help me guys please

 

[Phazoner]

Which is your power supply?

 

[anas.angel55]

Xigmatek nrpvc600 600W 50 plus

 

[Phazoner]

Check your temps installing Rivatuner + MSi Afterburner and setting this one to display GPU and CPU usage and temperature.

 

[anas.angel55]

Gpu from 45-55 C
And Cpu from 45-50 C

 

[dudeman509]

Is HDD usage high at times of lag?

Leave task manager/resource monitor open and look for disk usage spikes

 

[anas.angel55]

No it's not