Loss of performance with Manli RTX 3080 10GB?

In advance: PC information: Manli RTX 3080 10GB, Ryzen 7 3700x, 16GB Ram

Hello,

yesterday I received my beautiful RTX 3080 from Manli and got it with a PCIe cable like this one: "https://www.amazon.de/Thermaltake-Gaming-Riser-Cable-200mm/dp/B073S142CW/

Now I've installed all the drivers and wanted to start playing.

Before I bought it, I saw a video where someone was playing with the Fortnite card: "

There I chose the same settings as you can see in the video for Low Settings and Full HD.

Now it reaches around 450-500 FPS whereas I only reach 250 FPS.

The settings were taken exactly from the video.
What is that?

I don't think that my processor can't pack the performance, or can't keep up, because it actually already has a lot of power.
Is it because of the PCIe cable?

I would be happy about any reply!

Always these comparisons with YouTube videos.

Even if you had the exact same system, you wouldn't get the same FPS.

What is your 250 FPS not enough for now?

How are the FPS without riser cables?

The only problem is that I wanted to get a 240hz monitor.

And in some game situations, the FPS drops to 120. The monitor is simply not worth it. I also had 220FPS with my old card. Then the acquisition would have been for the cat.

I'm not home right now. Try later without the cable.