Question why cant I run fortnite with stable 144 fps

[Electrified]

my problem is that I can't run fortnite or multiple games at steady fps they bounce a lot regardless if i lock them at 144hz i recently bought the monitor BENQ xl2411p 144hz and had 8 gbs of ram so i decided to get another 8 now i have 16 but i cant even keep steady fps on fortnite at 144 on epic settings with low shadows and effects fps when keep dropping a lot theyre never steady.

so basically I have a i7 4790k 4.0 GHz hyperx 16gb ram 1866 MHz EVGA GTX 1080 2 ssh hyper x 250gb and another ssd samsung evo 500 gb

https://imgur.com/a/5WeaNlU

View: https://imgur.com/a/5WeaNlU

 

[drivinfast247]

Framerates do bounce around. That's what happens.

What speed is your RAM operating at?

 

[Electrified]

Framerates do bounce around. That's what happens.

What speed is your RAM operating at?

My ram usage is prob like 35-45% but im saying lets say i just stay in one place frames bounce crazy regardless if im in creative in an empty map on fortnite