[Intel I5] - Problem of Threads

[laima45]

Hello,

I am experiencing the following issue: I have an Intel i5-1600KF processor with the following specifications: 4 cores and 20 threads.

AndouinOS correctly detects all the threads, but they are never fully utilized.

I ran tests using Cinebench and Cyberpunk 2077, and only the first 12 threads are being used.

Do you have any solution to this issue?

[Anduin2017]

Version please? Can you share the output of sudo inxi -b?

[laima45]

[Anduin2017]

i5-13600KF Arch：6 P-Core (with hyper threading, so 6x2=12 threads) + 8 E-Core。Totally 20 threads.

And only P threads are running and working for the gaming. It might be expected.

Gemini said that:

This is a very typical **Intel Hybrid Architecture** scheduling problem.

First, let's correct a misconception in his hardware description: he doesn't have "4 cores"; `inxi` has clearly identified it as having **14 cores** (6 performance P-Cores + 8 energy-efficient E-Cores).

**My analysis is as follows:**

1. **The math matches perfectly:**

* **i5-13600KF architecture**: 6 P-Cores (supporting Hyper-Threading, i.e., 6x2=12 threads) + 8 E-Cores (not supporting Hyper-Threading, i.e., 8 threads). A total of 20 threads.

* **Current user situation**: Only 12 threads are working.

* **Conclusion**: **The system completely ignores the 8 E-Cores**, running only on the P-Cores.

2. **Kernel recognition is normal:**

* `inxi` output shows: `14-core (6-mt/8-st)`. This indicates that the Linux kernel (Kernel 6.17) is aware at the underlying level that this CPU has 8 single-threaded cores (E-Cores).

* Since the kernel recognizes it, but benchmarking (Cinebench) and games don't utilize it at all, the problem is most likely in the **BIOS settings** or **Grub kernel parameters**.

**Possible solutions (suggested response approach):**

I suggest you have him check the following points, the most likely cause being that the "Legacy Game Compatibility Mode" in the BIOS is triggered:

1. **BIOS "Legacy Game Compatibility Mode"**:

* The MSI motherboard (it's an MSI PRO B660M-A) has a feature that, for compatibility with older anti-cheat systems (DRM), allows dynamically disabling E-Cores via the **Scroll Lock** key on the keyboard.

* **Troubleshooting Methods:** Have the user check if the Scroll Lock LED on the keyboard is lit, or disable this feature in the BIOS (usually in the CPU settings). If this feature is enabled and active, E-Core will be hardware-disabled.

2. **AVX-512 Attempts in BIOS:**

Some users attempt to disable E-Core to force AVX-512 (although most 13th generation CPUs do not support it). Have the user check if E-Cores are manually disabled in the BIOS.

3. **Kernel Parameters (Grub):**

Check if `GRUB_CMDLINE_LINUX_DEFAULT` in `/etc/default/grub` contains `isolcpus` or parameters that limit the number of CPU cores.

The fact that you are stuck at exactly 12 threads strongly suggests that your 8 E-cores are inactive or disabled, leaving only the P-cores running.

Since the kernel sees them (8-st), this is likely a BIOS configuration issue. Please check the following on your MSI PRO B660M-A:

1. Legacy Game Compatibility Mode: Check if this is enabled in BIOS. On MSI boards, this feature parks/disables E-cores when the Scroll Lock key is active on your keyboard. Try toggling Scroll Lock or disabling this feature in BIOS.
2. E-Core Control: Ensure 'All E-Cores' are enabled in the CPU configuration settings in BIOS."

Can you try that? Or maybe just some game prefer running only on P cores for better performance?

[laima45]

Legacy Game Compatibility Mode : Already Disable
E-Core Control: Already Enable