Avast installed slows down my LAN speed from ~940 Mbits/sec to ~705 Mbits/sec

Hello,

I have been using Wifi but recently ran an ethernet cable to my laptop.
I was getting less than desirable LAN speeds with the built in gigabit adaptor so I bought a USB 3.0 RJ-45 adaptor but turns out it was actually Avast slowing down my speed.

I figured this out after a fresh Windows 10 Pro x64 Install with latest updates installed using iperf3.exe to test LAN speeds:

Before Avast installed: ~1.09 GBytes ~940 Mbits/sec
After Avast installed: ~840 MBytes ~705 Mbits/sec

After removing Avast (using avastclear.exe) speeds return to full speed.

Avast installed doesn’t seem to affect the USB 3.0 to RJ-45 connection but it is slower than the built the built-in RJ-45 (when Avast is not installed).

Here is the built-in RJ-45 information:

Marvell Yukon 88E8059 PCI-E Gigabit Ethernet Controller

Driver Provider Microsoft
Driver Date: 4/11/2013
Driver Version: 12.10.17.0
Digital Signer: Microsoft Windows

Thanks.

https://support.avast.com/article/Troubleshoot-Antivirus-Web-Shield