XPS 8940, slow internet after system refresh

Uninstall all of the Killer software leaving only the drivers and see if it helps.

Still have the Killer S/W installed? Check to see if it is NOT inhibiting the speed? Click on the settings, something like a 'gear' on the upper right. Auto Bandwidth should be off. You can also select Set Bandwidth that will you to TEST the speed and also set it.

A few things to look at, first I'd verify that the Tech did NOT replace your cable to the PC with a 100Mbps cable.

Also speed tests vary greatly.

For instance, I'm using the wireless built-in Killer card, and have 1GB service from Spectrum. I know 940Mbps or so is the max., and I've gotten close some days.

Not ALL speed tests will give you the same results. For instance, these are the Killer S/W and Spectrum test site results:

@ispalten​ Thank you also for responding.  I wish the emails to let you know you have responses was working again.  Anyhoo...

I do not have the Killer software installed.  Should I?  I had read about the 'prioritization engine' I believe causing issues.

I took the cable that the tech had given me and replaced it with my own that I had gotten the normal speeds on before.

I just ran a speed test on my phone (I always use speedtest.net) and my 300mbps came in normal.  I did a little while ago on the Fire TV and it was fine.  Of my 300mbps the speed test I just took showed a download of 152.63.  I know it can vary so I ran it again and just got 118.  I did call Spectrum and they were showing speeds of 390 at my modem.

@figureguy​,

No, you don't need the Killer S/W. I keep it running for other reasons.

By the way, I didn't mention, but sometimes little things like a mismatch in Security can cause problems too.

One of the reasons I own my OWN router. You have no access to Spectrum router/modem's to check anything.

So Spectrum says you are getting 390Mbps... for 300Mbps service that seems high, they usually only over provision by 15 to 20 Percent.

So, the next test, feed the WAN feed from the wall into the PC and test... that takes the router out of the equation. Still getting 100Mbps, something going on in your PC.

I re-read you initial message, Switch is getting full speed and is wired? Use its port.

Bothersome you say Wireless on the XPS is still low, others are not?

I assume other devices you use wifi on are all Wifi5 or 6 capable.

Research the Modem/Router or if individual parts, the router, make sure it has Ethernet ports that are 1GB (I sure they are, but check anyway).

Also I assume you have more than one Ethernet port out of the Spectrum device? Try a different one. See if it changes.

I am assuming you XPS has the same Killer device I do, the Wi-Fi 6 AX1650i?

If so, maybe you should reload from Intel the whole latest release?

You can get it from here, https://www.intel.com/content/www/us/en/products/sku/211610/intel-killer-wifi-6-ax1650-is/downloads.html, the Killer Suite is what you want.

Might also want if you do not have it, the Intel Driver and Support Assistant, you can get it here ==> https://www.intel.com/content/www/us/en/download/18002/intel-driver-support-assistant.html?wapkw=intel%20driver%20and%20support%20assistant%20download as it will check and install any needed Intel driver.

Is Device Manager correctly recognizing both network adapters?  If it sees the Killer Ethernet adapter, is this driver installed?

And do you have the latest driver from Dell for whichever Killer WiFi card you have?

Did you check in Start>Run>services.msc to make sure you don't have any Killer services running (even if you don't have their app installed)?  Set Startup type for any Killer services listed in services.msc to Disabled. Then reboot the PC and see if that helps.

@ispalten​ I did download Killer.  I went to priority and made Firefox number 1.  Then I ran a speedtest and got 116mbps.

Actually I don't have a wan from the wall.  My modem is connected by a cable wire to the modem, and from there the Ethernet to the router.

I did try and use the switch port.  Same results.  In fact I did try all 3 ports on the router, and even went directly to the modem and bypassing the router.  Same results.

I have installed Killer E2600 Gigabit Ethernet Controller.

I downloaded the Intel Driver and Support and it came up needing the drivers for the Wireless Bluetooth and the Killer performance suite.

The only thing I can think of next is to have my wife bring her laptop home from work and see if I wire that what happens during a speedtest.  I will admit I have some PC knowledge, not an expert by any means, but I am just stumped as to what it could be except a problem with the PC itself.

I did just go into Killer and shut off the Prioritization Engine and just got a download of 181.51.  I ran it a second time and got a 181.74.

What else should I do for settings in Killer to help with the speed?  I am not familiar with the program.

I just ran Speedtest from within Killer and shut off ALL options in settings.  I went to set Bandwidth and got a 249.  Through Firefox 179. 

Thanks for your time and effort.

If I go into settings and turn Prioritization on, how do I change what order streaming, download, gaming, etc. is in?

@RoHe​ Thanks for responding.  I installed the ethernet driver you directed me to.  In order to do it I had to uninstall the Killer S/W as it said it could not install the driver while that was installed.   I also went into services.msc, stopped all Killer services and then disabled them. 

I just ran a speed test and got 200.70mbps.  Upload is 11.59, but while download has been slow upload has been consistently perfect.  Ran it again and got 173.67.

If it is consistent a little better but still not right. 

I just ran a Dell System Diagnostic and I got this about the Ethernet card.  I'm not sure what it tests for or means but my system is out of warranty.

One last thing, I tried to run a Safe Boot with Networking and I got this message:

You're connected using a virtual network adapter that we can't test

@figureguy​ 

First, the Prioritize Engine...

You do NOT need it at your speed, at least not unless you have many people using your LAN and are a Gamer and not getting enough speed or responses, then you'd use it to boost your speed on a specific device or program.

On that same page though, you see Current Bandwidth Settings, it should be set to your speed of the Internet Service, including the Over Provision, so it should be 400 Mbps in your situation.

Secondly, you wrote "Actually I don't have a wan from the wall.  My modem is connected by a cable wire to the modem, and from there the Ethernet to the router.". I assume you meant wall cable to modem, and modem output to your router and via a router Ethernet port to your PC. If so, it is the cable GOING into the router, the one coming from the modem to the router that you should plug into the XPS... I see it was my error that confused you when I posted from the wall. It is the cable from the modem then should go into the XPS which bypasses the router that is to be used. This would rule out the router as the cause?

Which reminds me, normally problems can happen if there is a 'mismatch' between the modem and router, especially if one is changed. So I wonder IF your router was left one while the modem was replaced by Spectrum? That could cause a problem, and the 'fix' is easy.

Try this, power off the PC, Router, and Modem. Then power on the Modem and WAIT for the 'Internet icon', a globe or the light next to Online is on, on the Modem. Next power up your router. When it is fully up and its Internet light is on, then power up the PC and test.

If the Router was part of the problem, this could clear it.

I assume you own the Router (not Spectrum's) and can see its settings. Some even have Internet test capability? If it does, test on the Router for speed. If the router itself has QoS setting, turn it OFF, again, with 300Mbps service, it is not needed.

Last thing to look at. On the Device Manager in Windows, look at the E2600 Ethernet Controllers Properties... and check its speed setting.

Actually the Device Manager for the Ethernet was showing what you specified.

I am trying another pc reset with saving files but it has been at downloading 100% for almost an hour now.  I went in through settings, recovery.  Is that normal?

I did go from the modem directly to the PC with Ethernet, no change.

When I go to Killer Intelligence center now, it says service not running.

@figureguy  -Glad you got it working now.

Just be on the lookout for another Intel/Killer update via Windows Update.  It's currently listed as an optional update on my XPS 8930 (Win 10) but sooner or later WU will probably force-install it.  And it will likely re-enable the Killer services in services.msc and their apps too, which will likely mess up the internet connection speed again.