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Without any prior warning the CPU in my laptop (an Acer V15 Nitro) is now always throttled to 400MHZ, which is very annoying of course.

I've played around with detaching the battery for some time, booting and rebooting with the HDMI cable attached or unattached, I booted into 18.04 (I run 19.10), same thing.

Only thing that made a difference, was to go to sleep mode and then wake the machine up again. For a short moment, the throttling is gone and the cpu does what it should. However, the moment I start a program the freq drops to 400 again and stays there.

The only difference that I noticed is that the cpu fan seems to be making clicking sounds. Every 8-10 seconds it clicks a few times. I am not sure if this is connected.

I tried to run pwmconfig in hopes of finding out if something is wrong with the fan, but it just returned that there are no pwm-capable sensor modules installed. (sensor-detect didn't help either)

Here's what lscpu spits out:

Architecture:                    x86_64
CPU op-mode(s):                  32-bit, 64-bit
Byte Order:                      Little Endian
Address sizes:                   39 bits physical, 48 bits virtual
CPU(s):                          4
On-line CPU(s) list:             0-3
Thread(s) per core:              2
Core(s) per socket:              2
Socket(s):                       1
NUMA node(s):                    1
Vendor ID:                       GenuineIntel
CPU family:                      6
Model:                           78
Model name:                      Intel(R) Core(TM) i7-6500U CPU @ 2.50GHz
Stepping:                        3
CPU MHz:                         400.001
CPU max MHz:                     3100,0000
CPU min MHz:                     400,0000
BogoMIPS:                        5199.98
Virtualization:                  VT-x
L1d cache:                       64 KiB
L1i cache:                       64 KiB
L2 cache:                        512 KiB
L3 cache:                        4 MiB
NUMA node0 CPU(s):               0-3
Vulnerability Itlb multihit:     KVM: Mitigation: Split huge pages
Vulnerability L1tf:              Mitigation; PTE Inversion; VMX conditional cache flushes, SMT vulnerable
Vulnerability Mds:               Mitigation; Clear CPU buffers; SMT vulnerable
Vulnerability Meltdown:          Mitigation; PTI
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1:        Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2:        Mitigation; Full generic retpoline, IBPB conditional, IBRS_FW, STIBP conditional, RSB filling
Vulnerability Tsx async abort:   Not affected
Flags:                           fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
                                  syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmpe
                                 rf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt
                                  tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti ssbd ibrs ib
                                 pb stibp tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed a
                                 dx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_ep
                                 p md_clear flush_l1d

I'd be very grateful for any ideas or tips to solve this problem.

Edit: Sensor info. At these temps the CPU was throttled already.

pch_skylake-virtual-0
Adapter: Virtual device
temp1:        +47.5°C  

BAT0-acpi-0
Adapter: ACPI interface
in0:         +12.60 V  
curr1:        +1.15 A  

ath10k_hwmon-pci-0300
Adapter: PCI adapter
temp1:        +39.0°C  

coretemp-isa-0000
Adapter: ISA adapter
Package id 0:  +47.0°C  (high = +100.0°C, crit = +100.0°C)
Core 0:        +47.0°C  (high = +100.0°C, crit = +100.0°C)
Core 1:        +44.0°C  (high = +100.0°C, crit = +100.0°C)

acpitz-acpi-0
Adapter: ACPI interface
temp1:        +47.0°C  (crit = +99.0°C)
temp2:        +41.0°C  (crit = +92.0°C)
  • Intel CPUs throttle when they get hot. Turn it off and let it cool down. Take it outside or someplace cold and power up; does it run at unthrottled speed for longer? – K7AAY Jan 23 '20 at 22:39
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    Can we get your CPU temperature? https://askubuntu.com/a/854029/307523 – WinEunuuchs2Unix Jan 23 '20 at 23:18
  • The clicking noise that you hear might actually be the HDD failing. Unrelated to anything with the fan. Do you hear the fans turning at a high speed? Do you have any temperature utilities like lm-sensors installed so you can see if you have a heat-related problem? – heynnema Jan 24 '20 at 00:03
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    @K7AAY it now ran for a bit longer than usual, after having it switched off overnight. But not longer than 5-8 minutes or so. – Viktor Gruber Jan 24 '20 at 09:23
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    @WinEunuuchs2Unix @heynnema Conky doesn't seem to load, but this is what the sensors command gives me: `Laptop:~$ sensors pch_skylake-virtual-0 Adapter: Virtual device temp1: +40.5°C

    Adapter: PCI adapter temp1: +39.0°C

    coretemp-isa-0000 Adapter: ISA adapter Package id 0: +41.0°C (high = +100.0°C, crit = +100.0°C) Core 0: +41.0°C (high = +100.0°C, crit = +100.0°C) Core 1: +38.0°C (high = +100.0°C, crit = +100.0°C)

    Adapter: ACPI interface temp1: +40.0°C (crit = +99.0°C) temp2: +39.0°C (crit = +92.0°C) `

    – Viktor Gruber Jan 24 '20 at 09:26
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    At these temps, the laptop got slow again. – Viktor Gruber Jan 24 '20 at 09:26
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    I am now pretty positive that the fan is broken. Butn ow I am wondering why it'd be throttling so early, when the CPU didn't even have time to heat up yet. – Viktor Gruber Jan 24 '20 at 09:28
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    Found this: https://community.acer.com/en/discussion/587408/cpu-always-throttled-fan-clicking and https://askubuntu.com/questions/1204610/cpu-throttling-all-the-time-in-ubuntu-16-04 and https://linustechtips.com/main/topic/449512-cpu-throttle-gpu/ – WinEunuuchs2Unix Jan 24 '20 at 11:51
  • Viktor, when you paste data into a Comment, it loses all formatting,. Henceforth, please use [edit] and put the data into the question which does have formatting; data's a lot easier to read there. Editing tips are at http://askubuntu.com/editing-help#code - - Also, think opening up the laptop to check the CPU fan may be the solution. I am unable to find a service manual from Acer but third party guides abound https://www.google.com/search?q=Acer+Nitro+V15+service+manual – K7AAY Jan 24 '20 at 18:15

1 Answers1

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So it turned out the problem was indeed the CPU-fan. I got a replacement, installed it, and now even under heavy load the CPU is not throttled.