I don't have a solution but I have the same problem! What I've discovered is the CPU will force all tasks into a single thread and change the active thread every 10-15 seconds. I've also done everything under the sun to try and narrow down this problem.

I've done everything you mentioned plus:

• Modified CPU settings in BIOS to force behavior change.
• Disconnected all peripherals.

Are you using Windows 10 or 11? I've got 11 and I've considered setting it up with 10 instead to see if that makes a difference.

Are your laptops also running a Core i5-1240P?

Thank you for your reply @carrellslake 

We are using Windows 10 and were considering setting it up with Windows 11 - that saved us some efforts.

We also did some CPU stress tests and found that under prolonged CPU load the performance gradually degrades until at some point enters what I think is "low performance mode". This is good for short term heat reduction, but the problem is the CPU doesn't exit that mode unless you restart.

We are also considering testing with disabled "Intel Speed Step Technology" option in the BIOS, but that will be tomorrow.

Edit : CPU is Core i5-1240P too

I tried multiple BIOS setting changes related to CPU performance and nothing helped. I can confirm, at least for my laptops, that CPU temps are not the problem either.

I suspect the fix for this may be related to the processor itself. Intel might have to be the one to provide a solution.

One more thing I forgot to mention - we tried also to edit the Windows power plan and reduce the "Maximum processor state" to 70% . So far the laptop is working a bit more stable, but this is more of a temporary workaround than a solution.

This is good for short term heat reduction

Rolling back to May BIOS 1.2.2 seems to improve the situation.

The only issue now is disabling Windows update BIOS enforcement until a more stable version is released.

@carrellslake  please test and share results if you can

Thanks for the suggestion, I'm trying it now. Since it happens somewhat randomly, it could be days before I think this is the fix.

I am also currently also experiencing the same issues with CPU usage, the issue is intermittent. It seems that when the Windows Update installs the Windows Drivers from Intel (INTEL - System - 10.1.45.4 &INTEL - System - 10.1.36.6) the system becomes very unstable. 

This is a very temporary solution and not a very effective one as I had to disable driver updates.

Also, all updates for drivers were done using DELL Support Assistant. 

Has anyone found a more permanent solution for this issue?

FYI Dell Command Update application can also push the BIOS update.

I am also experiencing this issue on a Latitude 5431 with an i5-1240P on Windows 11.

I haven't been able to figure out what it is, but once a certain threshold is exceeded, whether it's temperature or CPU usage, the system will throttle, and only utilize a single CPU core (of 16) until the system is rebooted.

I was able to replicate it by pushing the CPU above 50%, by opening a bunch of Youtube videos, roughly until the fan speed kicks on indefinitely.  After that I close everything down and the CPU usage drops back to normal, however everything becomes so much less responsive to the point where it's unusable for any sort of productive work.  The fan also remains on high, even though the temperature has dropped back to normal, and no heat can be felt.

Looking at the Performance tab in task manager and in HWMonitor I can see that only a single CPU core is working, and the speed is well above the 1.7GHz base, indicating that Turbo Boost has likely remained active.  Only after a reboot does the system return to normal.

See my screenshot below:

Under normal circumstances there would be utilization on all cores.  Even in cases where all cores are active, and the CPU usage is above 90% the system is more responsive than when this problem is ocurring.

I'm on the latest BIOS version 1.70, 16GB RAM, i5-1240P.

Please look into this, Dell, because this is an otherwise high performing processor.

Thanks.

Greetings community

I am still looking for a solution, and my organization also has the same issue. We purchased a batch of this 5431 and experiencing the same issue. I chatted with one of the Dell engineers, and he mentioned they have been getting a lot of jobs on the 5431, and it CPU related, and motherboard replacement doesn't seem to fix the problem.

Thank you

Same issue here. I can add info, that if Type-C power supply is attached, then the issue arises. On battery mode (with default Windows power scheme) we have no issue. As I read this topic I'm sure that this is not a warranty case yet. I believe, that DELL team will release a new BIOS asap.

Please drop a comment if correction for 1.7.0 is available.

Prior thanks.

I've downgraded the BIOS to 1.2.2 and haven't experienced the issue again.  So definitely an issue with the latest BIOS and the CPU. 

I asked Dell representative a week ago about this issue. He heard nothing. But offered a mainboard replacement as notebbok is under warranty. I refused as no make sense and explained to him that I will wait till an official BIOS update is available.