XPS 8940, updated to Windows 11 Pro, sluggish and slow

My desktop is an i9 9900K.  On Win 11 and no change in operation.

Check for driver updates (And Support Assist update) as a driver may be causing the problems. Drivers/BIOS updates should have been done before upgrading.  Settings/System/Recovery has an option to return to Win 10.  If you can't get it sorted that may be the best option, go back to Win 10 then do any driver/BIOS updates then upgrade to Win 11.  

I saw another thread (different model) that was having a Win 11 issue that appears to be a driver.

So far there are no Win 11 drivers posted for the XPS 8940 on its Support page. There is a brand new BIOS update, but that probably won't fix "sluggish".

You might try resetting BIOS to system defaults and see if that improves things...

I had the same issue and it was bugging the heck out of me.  I couldn't even play Starcraft as it was super slow.  I ran the userbenchmakr and it showed me that my CPU (i7-1100) was underperforming.  My system was below average performance.  I was shocked!  I updated all the drivers, bios, swapped out video cards with an nvidia 1080 and still the same problem.  

I ended up backing up my data, and went back to Windows 10 and guess what?  It's SUPER fast again.  I ran the Userbenchmark again and this time it said:  'With an outstanding single core score, this CPU is the cat's whiskers: It demolishes everyday tasks such as web browsing, office apps and audio/video playback. Additionally this processor can handle typical workstation, and even moderate server workloads. Finally, with a gaming score of 94.1%, this CPU's suitability for 3D gaming is excellent.'

Spec: 

Core i7-1100, 64 GB memory, 2TB Western Digital NVMe Black, Nvidia GTX 1070

So there must be some compatibility issue with the XPS 8940 and Windows 11.

I hope Dell or Microsoft can work together to resolve this issue.

@ckao How long ago did you revert to Win 10?

What version of BIOS is installed?  (You don't want v2.4.0 which is causing problems, so use v2.3.0.)

Did you update all the drivers after installing Win 11, including the recent Win 11 driver update for the GTX 10xx card?  When this thread was started, Dell hadn't yet posted the Win 11 drivers which are available now.

Hi RoHe, I reverted back to Windows 10 yesterday and I am so happy I did.  

To answer your question, yes I am on Bios version 2.4.0. I didn't know version was causing problems with Windows 11.  

With the Video drivers, yes I was running the latest version. I got it from Nvidia's site.  

I was trying to hard to figure out what the deal was with my machine and it was definitely the CPU not performing to it's max.  According to the Userbenchmark program, it was clearly the CPU.  In Windows 11 it was bad .  In windows 10 it was like a super CPU. 

So you think downgrading the bios will fix this problem in Windows 11?  I also do notice my machine freezing up from time to time using bios version 2.4.0.  Maybe I'll try version 2.3.0 per your suggestion.

Thanks for responding back!

BIOS 2.4.0 has been causing freezes/crashes with both Win 10 and Win11 for lots of XPS 8940 users. Have you not seen that happening with 2.4.0 on your PC?

If you plan to revert to BIOS 2.3.0, you have to enable the BIOS roll-back option in BIOS setup first.  And as soon as it's rolled back and PC is working normally, open BIOS setup again and disable "UEFI Capsule Updates" to prevent Windows Update from installing 2.4.0 again.

It's usually better to get drivers that Dell validated in Win 10 or Win 11 with their OEM NVidia cards.

If you hadn't already gone back to Win 10, you could have looked in Task Manager or used Process Explorer (free from Microsoft) to see what was hogging the CPU and causing poor performance, which could have helped you find/fix the problem.

Since Win 10 is working well, you probably should stay with it. Microsoft will support Win 10 until Oct'2025 so there's lots of time for them to kill all the bugs in Win 11.

I had a similar problem - not directly related to any software update but I ended up realizing I had caused it by changing the way a secondary monitor was connected.  I replaced an old second monitor with a new one (from Dell) and instead of using the DisplayPort <-> HDMI adapter I used on the old secondary monitor, I decided to just plug the HDMI cable from the new monitor to the main HDMI port on the machine.  Big Mistake.  Changing back to using my nVidia GeForce graphics card completely resolved the performance problem for me.