ROG CROSSHAIR X870E HERO: LAN speed drops to about 90 Mbit/s

[LeDierck]

Hello @all,

I’m using a ROG CROSSHAIR X870E HERO motherboard (BIOS 1715) with Windows 11 Pro (latest update).
The PC is connected via LAN cable to a Fritz Cable Box (400 Mbit/s). In speed tests I consistently get around 430 Mbit/s.

For the past few weeks, however, I’ve been experiencing an issue: after some time, the LAN speed drops to about 90 Mbit/s. If I disable and re-enable the network adapter, the full speed immediately returns.

It’s not related to the router or the internet connection itself — I’ve tested with other devices and they always get full speed. The same applies when I disable LAN and switch to Wi-Fi on the PC: full speed is available there too.

The network adapter is a Realtek PCIe 5GbE Family Controller. The latest driver is installed, and all power-saving options are disabled.

Does anyone have an idea what could be causing this problem?

Thanks for you assistance in advance!
Best, LeDierck

[Brainbl33d]

I would check to see if there's any firmware updates available for your Realtek PCIe 5GbE Family Controller/Wifi Adapter.

[LeDierck]

Hi Brainbl33d, 
Thanks for your hint. I've updated the driver and additionally I've ordered a new LAN cable CAT 8.1. 
I think that should solve this problem. I will report...