Lan connection to laptop 1 approx. 250 Mbit / s to laptop 2 approx. 100 Mbit / s why?

Both computers are connected directly to the router and with the same cable length. Both are absolutely identical, what could be the cause?

If you are connected via Wi-Fi, both have approximately the same values of approx. 100 Mbit / s.

Fritzbox 7590 and two Akoya E7211 notebooks about 10 years old.

Too little detail…

Both notebooks connected to the same Lan cable / Lanport on the router and compared? Another cable can be to blame, router port can be set differently…

Drivers may not be identical or configured differently. Technical defect that no GBit LAN is recognized. You can check if you have the network status displayed, whether the LAN connection is only 100MBit to the router or whether Gbit was detected…

I have already swapped and compared both cables and the router inputs, it always stays the same laptop slowly. I've already removed drivers from both of them and installed the latest Marvell Yukon 88E8057 PCI-E Gigabit Ethernet controller, but that didn't work either. I'm slowly starting to believe there's a technical defect or can you think of anything else that could help? In any case, many thanks for your efforts.

LAN connection on both devices 1000/1000 (Mbps)