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February 16th, 2026 21:49
XPS 8940, internet upload speed slowed down again after Windows Updates last week
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!
TheRoots
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February 17th, 2026 22:13
@ispalten Thanks for the additional information. I downloaded the Killer Performance Suite directly from Intel's website (dated 01/06/2026, version 40.25.1125.1924). I have seen other posts mention using the Intel Driver App can cause unexpected results. I also saw it happen with my Dell Inspiron 16" 2-in-1 laptop. So, I opted to just download and install the Killer App and Drivers only. This installed the Killer Intelligence Center App and updated the drivers:
1) It updated the Intel Corporation - Extension - 3.1423.712.2.
2) But, backed off the Intel Corporation - Software Component - 3.1423.712.2 to the previous version.
After doing this, my Internet speed (as reported via the Microsoft store Ookla App) is back to normal. However, it was still erratic when I was surfing the web. Sometimes it was slower to respond, even though the Ookla App was still saying the speed was 700+Mbs (Download) and 40+Mbs (Upload). So, I went into the Killer Intelligence App and turned turned the Killer Prioritization Engine OFF. This change seems to have stabilized my Internet speed across everything. Maybe this too will prevent future updates from Windows Update from affecting the Upload speed again, by having the Killer Apps installed but turned off.
The Killer E2600 driver now has a date of 09/19/2025 and version of 1168.27.50.919. Since my problem seems to have occurred following a Windows Update, I wonder why it installed an older driver than what is current on Intel's website.
Unless this comes back with the next Windows Update Patch Tuesday, I think I am all set. Thanks again for your help.
ispalten
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February 17th, 2026 01:25
Hmm,
We seem to have some differences on our 8940's?
What I see for properties:
Some differences for sure, Driver Date and Version? Also Properties look different? I'm on W11 Home 25H2 if that matters.
Run the Intel Driver and Support app and see if it finds newer Killer drivers?
I am NOT using the Ethernet though as I am WIreless. I have 1GBps service, and a Wifi 7 router. I replaced the on-board Intel M.2 network adapter with the Intel WiFi 7 BE200 M.2 adapter. I get 940Mbps wireless. Same adapter that shipped on my wife's Dell Tower Plus.
TheRoots
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February 17th, 2026 04:48
@ispalten ,
Do you have any of the Killer Apps running in Task Manager? Have you tried your Wired Ethernet connection to see if it still works correctly?
ispalten
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February 17th, 2026 14:02
@TheRoots
I did NOT when running Wireless.
OK, I did switch over to Wired. Doing so caused this ONE Service to start:
Which also loaded these:
None of that is normally running.
So I changed over to Wired, the test results using Speedtest via the Web Browser that can be lower than the desktop version due to more network load.
I got this:
I'd say about normal for testing that way. Note my UPLOAD speed it the max possible.,
With that Killer stuff loaded, I want back to Wireless, WiFi 7 MLO SSID:
Upload, the same, download, a little faster. However, some Killer items are running:
So I ended all those, retested wireless, and about the same down and up.
Knowing I do better than that, I started the OOKLA Desktop app that goes between the PC and my ISP directly, without all the hops and jumps between the PC and the OOKLA server on the web.
As expected, my wireless was much better:
So make of it what you will. I really think it could be your older driver, check Intel's site to update it.
I do have the Killer Performance Suite that was installed on 2/5/2026, but it is not active unless I use Ethernet. My Wireless is via a TP-Link Wifi 7 PCIe card, or the Intell BE200 M.2 Adapter which I can also use. Both wireless adapter's perform about the same, but the BE200 handles MLO better, but in terms of speed, I can't tell the difference.
TheRoots
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February 20th, 2026 05:17
Just for future reference if anyone else finds this and has the same problem, I downloaded the latest version of the Intel Killer Performance Suite from;
https://www.intel.com/content/www/us/en/download/19779/intel-killer-performance-suite.html
Element115s4
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328 Posts
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February 21st, 2026 19:22
For grins, I installed that INtel Killer Perf Suite onto an XPS 8940 and it dropped the performance to 25% of what it was via WiFi. (Rough numbers = 400/400 down to under 100/100).
After uninstalling, it's back to normal.
I didn't see the same thing with my XPS 8950 via wired using the same download but now I wonder if it's degrading my speeds a bit
:O
TheRoots
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February 21st, 2026 20:12
@Element115s4 , That is interesting.
If anyone is still reading or following this post, do you think you get better Internet speed with the Intel Killer Performance Suite uninstalled versus installed and turned off?
I'm just hoping there's a way to get the best Internet speed I can without the Killer Performance Suite reinstalling/upgrading with a Windows Update and causing the problems all over again.
I really find it odd that Intel would create an App that prioritizes upload speeds this way. It seems like if you are doing anything other than gaming, the upload speed is always at 10% of the full speed, even it no game is running at all. I don't even have a game installed on my XPS 8940.
Element115s4
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February 22nd, 2026 17:13
@TheRoots
There is an impact when running the Killer PS and I re-ran with it disabled.
I may uninstall to see if that changes anything.
TheRoots
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February 22nd, 2026 20:45
@Element115s4 , Thanks for the information. What services do you disable? It looks like I have 5 Killer services running? Is it just the Killer Performance Suite that is causing the problem?
Element115s4
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328 Posts
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March 7th, 2026 15:05
@TheRoots
This is what is disabled on my 8950 atm but I'm not sure things are quite where they were before I installed the suite.