Why is Windows only showing 4 threads for a 12th Gen i7-1255U?

[JamesBrindle]

Windows, i.e. task manager, and other 3rd party software to measure CPU performance and identity (CPU-Z for example) seems to think my laptop only has 4 threads to play with:

It seems to know there are 12 logical processors, as seen in the screenshot above but it's only showing 4 threads...

I understand this CPU has 'P and E Cores' (2 x Power Cores and 8 x Efficiency Cores), but it looks like my efficiency cores are not detected, only the 2 power cores (with hyperthreading gives 4 logical processors).

Confirmed in the CPU-Z screenshot below:

(I believe it's supposed to say: 2P + 8E not just '2P'

At first, I thought the efficiency cores were switched off in the BIOS (I've heard older versions of Windows 10 doesn't play nice with efficiency cores, and my company still hasn't switched to Windows 11)... But there is nothing in the BIOS that will enable or disable or change any value with regards to the CPU....

Am I missing something?

[TzortzisG]

JamesBrindle, check Msconfig>Boot>Advanced Options to see if there is (for some weird reason) a CPU limit enforced there.

You are right that Win10 has various issues with post-11th gen Intel CPUs, due to the poor support for the new Thread Director technology. However, what you've posted is either a bug on monitoring applications, or the Efficiency cores are really not enabled, which is a big problem if true. I suggest you run this portable Real-time monitoring and tweaking program to see how your cores are really working...... You should see all the logical cores and their various states of usage on the main window, and if you press the Cstate button (C10), it will show physical cores and their Cstates.

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