T14s extreme throttling (<0.5ghz instead of 3-4.5ghz)
System: Thinkpad T14s with the Intel i7-1050U CPU, no dedicated graphics card, latest Windows 10 as OS, one external ThinkVision T27i monitor.
Problem:
The processor frequency drops to an extremely low value (0.3-0.5 ghz) and stays there (see picture below). As a consequence, everything stutters and becomes completely unusable. When I unplug the power supply, the frequency recovers after 1-2 minutes. Then I can plug in the power supply again and the frequency is normal again. HOWEVER, then the system is in a weird state where every CPU intensive (e.g. LaTeX compilation) action leads to the frequency dropping again (3.5ghz -> 2.5ghz). Normally, my CPU frequency goes UP when doing something like that (3.5ghz -> 4.0 to 4.5ghz). This weird state sometimes only resets after a deep shutdown.
When this problem appears:
- During video conferences it randomly appears.
- Sometimes just playing a youtube video triggers it.
- Using my Powered USB Type-C Travel Hub to connect a second external T27i display makes this problem to appear more frequently.
Regarding thermal throttling:
This is not normal thermal throttling. When the problem does not appear, I can play a 4k Video, where all 4 cores are between 88°C and 91°C (according to CoreTemp),
but the CPU frequency is still somewhat stable (2.7 to 3.5ghz).
Things I tried so far (unsuccesfully):
- Updated all drivers with Vantage.
- Installed the Intel Graphics Driver (non-Lenovo) for the integrated graphics chip.
- Updated BIOS.
- Checked Win 10 energy options.
- Checked BIOS configuration, tried different settings there. Tried a reset to default.
- Used another power outlet to power the ThinkPad.
- Disabled fast start, Uninstalled AHCI graphics driver and Lenovo power management driver in the device manager. Restarted and reinstalled specific drivers (thermal solution, system interface, PM device, graphics driver). This was suggested by phone support.
- Did the Lenovo system diagnostics (no problem detected).
- Disable HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesIntelppm with regedit (this only sets the frequency to 2.3ghz permanently).
- Uninstalled the Hyper V drivers in the device manager as this was suggested in another post.
In short: Something with the CPU frequency control/graphics chip/power management is deeply broken and sometimes makes my system unusable. Does anyone have any ideas?
