Why is there no connection to the router at high speed?

Question

network hardware

At home there is an Asus Wl-520GU router with DD-WRT v24-sp2 micro and a computer is connected to it via ethernet. After the upgrade, “I stopped accepting incoming packets” (something like that), and after a while I lowered the speed to 10Mb / s, and even then not always. Forced exposure to 100Mb / s does not help.
I tried to lower the speed in the network card driver settings to the above - everything works stably.
I've already tried everything - and change the drivers, and the cable, and the router to flash. It turned out that it only works at full speed through a switch, or if you connect it directly, for example, to an xbox.
Now I don’t know what to do - take a new router or is it all about the network card?

Motherboard - MSI H67MA-E45 with a network controller based on a Realtek RTL8111E chip.

Answer 1

Try updating your network drivers through the motherboard manufacturer's website . Or easier - you can do this .
There was the same problem with the integrated network from Marvel - it forcibly reduced the speed with the HP switch to 100 Mbps, although the adapter itself is gigabit.

Answer 2

Tried everything already

First you need to determine the cause, then fix it. Look up CRC errors on ports. Look at the logs.