Question / Help OBS Lags

[handiree]

Ok so basicly i wan to stream Fortnite...

My PC:

• Intel® CORE® i7-8700K 3.7-4.7Ghz, 12MB cache

• MSI Z370 KRAIT GAMING Mystic Light and Mystic Light Sync

• MSI GeForce GTX 1080 Ti GAMING X TRIO 11GB RGB LED

• Corsair Vengeance RGB LED 2x8GB DDR4 3200MHz C16

So when im not sreaming i have about 150-200 fps with vsync off and unlimited fps... but when i start to stream game fps stays the same but obs frame rate drops to 15-30fps...why? i fix it by limiting fps to 60 or using vsync...
why does this happen? is my pc that bad? like other streamers have wors pcs and stream perfectly at 60fps 720p without vsync or frame limiter...why?

 

[handiree]

log here

 

[handiree]

i guess nobody can help me...