Fortnite clocks down CPU?

Every time I start Fortnite my CPU clocks down to 800mhz. That's why I only have 30fps while playing. The i9 10900k and a 2080ti are installed. This problem only occurs with Fortnite. The temperature is 40 degrees.

How can I solve this problem?

The worse the game, the more clocked down = you will probably come to the TDP limit of the CPU, too much power consumption.

What else have you built in?

What can I do against it? Because until the latest update everything worked…

If only that's the case with Fortnite, it will probably be a mistake of the game. Do you have any tools from the motherboard manufacturer or something installed?