Very low download speed?

I have a problem. For example, if I An update from fortnite download, then there's usually 5-15mbits per second download, when I do a speed test there's 150 MBits per second. What can this be?

Because the 150 mbits are just a description. 150 ÷ 8 = the download per sec. So what you have ÷ 8 gives what you have in the sec

At the server connections to you.

the server being tested (150mb / s) is not the same as the fortnite server

Are the 18 mbits per second coming out still good?

And how. I only have 250 / kb per sec. Because of stupid copper pipe

Okay thanks!