Performance in game 5700x3d + 5070

Hello guys, i am wondering if what i am getting is normal ? I just upgraded my monitor to a dual mode one so when running fortnite , i am running my monitor in 1080p 320hz. i set the graphics settings to all low and dlss on performance to see how much fps i could squeeze and i am ggetting like 250 ish average but when i watch videos of similar set up, they are getting 300 plus to 400 fps on the same low settings and performance more on 1080p. I am wondering if i did something wrong or did turn something on ?

specs:

- 5700x3d

- 32gb ram 3200mhz

- Rtx 5070