Question realtek pcie gbe family controller slow speed

[Bixmox]

My ethernet cable is getting slower speeds than my wireless, what could be wrong?

 

[rgd1101]

network card, connection. or cable

 

[clsmithj]

I'm getting the same problem Realtek® GbE LAN chip (10/100/1000 Mbit) , 100MB+ down AT&T Fiber Internet, Brand new Cat6 ethernet.

This is a old new PC build I did last week. Using a Gigabyte 990FXA-UD3 rev 4 motherboard.

The slow internet became apparent when downloads were taking longer than usual and then I ran speed test and began getting these asinine rates:

Speedtest by Ookla - The Global Broadband Speed Test

Test your Internet connection bandwidth to locations around the world with this interactive broadband speed test from Ookla

www.speedtest.net

Meanwhile on my other desktop I recently built, on the same network but using completely different hardware, it's motherboard MSI X470 Gaming AC M7 , I run speed test and get decent speeds: https://www.speedtest.net/result/8253192632

These two PCs are sitting right next to each other, so I ruled out it having to do anything with distance. I suspect this LAN adapter on this board is going bad, but there is no way of to test this other than this is the results. Both PCs are running the same OS, Windows 10 Pro for Workstations.