Last week, after a Windows Update, the internet upload speed dropped from 40Mbs to 2.5Mbs. I'm using the wired Gigabit Ethernet connection. The download speed hasn't been affected and has been steady at around 700Mbs.

This happened once before, around 2 years ago, when I upgraded from Windows 10 Pro to Windows 11 Pro. At that time I saw a post on the Community pages that you could uninstall the Killer E2600 App. After I did that, my regular internet speed was restored to the normal 40Mbs. It has stayed at 40Mbs until last week.

However now, I don't see a Killer E2600 App in Control Panel\Programs\Programs and Features or in Settings -> Apps -> Installed Apps for me to uninstall. I am using Windows 11 Pro, Version 25H2, OS Build 26200.7840, Experience Pack 1000.26100.291.0.

1)  How do I restore my Internet speed to normal; 700Mbs (download) and 40Mbs (upload)?

2)  Is there a way to prevent Windows Update or Dell Command Update/Dell Support Assist from ever installing the driver or update that is causing this?

I have tried reinstalling the Dell Killer PCIe Ethernet Controller Driver from the Dell Support Driver website, but it fails:

Killer E2500/E2600/E3000/E3100/E5000 Gigabit Ethernet Controller Driver

Version: 34.23.7197, A54

File name: Killer-PCIe-Ethernet-Controller-Driver_22DM9_WIN_34.23.7197_A54_01.EXE

It looks like 2 Intel Drivers were updated on 02/11/2026, which is when I noticed my Internet speed changed. The updated drivers are:

Intel Corporation - Software Component - 3.1423.712.2

Intel Corporation - Extension - 3.1423.712.2

I'm attaching screen captures of the Windows Update history, Task Manager for the Killer Services running, and Device Manager for the Killer E2600 Gigabit Ethernet Controller. Has anyone run into this again? How did you resolve it? Is there a way to prevent it from reoccurring? Thank you very much!