The CPU speed shown in my task manager confuses me. It shows permanently 0,75 GHz. Is it normal (I mean, when I just browse in the Web, it probably doesn't need more...) or might be there any problem? My notebook is Acer Aspire 6920. Maybe I also should add that my fan is working all the time very loudly (at 2/3 speed, sometimes it goes full speed)

My task manager

  • Is your computer perhaps connected to AC and running without its battery?
    – Daniel B
    Aug 5, 2015 at 19:48
  • @DanielB why would it matter?
    – Liglo App
    Aug 5, 2015 at 19:49
  • Because of a limitation with this device generation. It wouldn’t hurt to answer the question, now would it? ;)
    – Daniel B
    Aug 5, 2015 at 19:53
  • It IS connected to AC, but battery is inside ...
    – Liglo App
    Aug 5, 2015 at 19:54

3 Answers 3


I am pretty sure that is just how much the CPU is being used at the moment. To check the speed that your computer really detects your CPU as, then:

1) Right click on "Computer", or "This PC" and select "Properties".

2) Under the "System" section, look at "Processor:", and you should see the detected speed of the processor to the very right of the name of your processor.

Edit: Looks like there is some sort of problem. I have a desktop with a similar CPU and while doing nothing it still uses a lot more than 0.75GHz.

Even though your CPU is a bit slower than mine, it should still go beyond 0.75GHz, take a look at how yours probably should look: enter image description here

  • Even the Task Manager (see Screenshot) shows 2,5 GHz.
    – Liglo App
    Aug 5, 2015 at 19:55
  • I just noticed that. Try doing something a bit resource intensive and see if it uses more of your CPU.
    – JohnDoe
    Aug 5, 2015 at 19:57
  • I also just noticed you have a CPU very similar to the one in one of my desktops, and that desktop is running Windows 10, so I am going to see if mine does the same thing.
    – JohnDoe
    Aug 5, 2015 at 20:00
  • after trying to do some intensive stuff it climbed only to 0,78 GHz :(
    – Liglo App
    Aug 5, 2015 at 20:28
  • 2
    I would see if the CPU is overheating like the first answer suggests. I would open up the computer and check for dust. Your CPU shows your computer probably came with Windows Vista and was probably made before 2010, so there is a chance dust has built up inside your computer over time.
    – JohnDoe
    Aug 5, 2015 at 20:42

If your fan speed is constantly high and your CPU speed is stuck at 0.75Ghz then it is quite possible it is overheating. If the fan is blowing hard and the air coming out of the exhaust is also fairly cool, this would reinforce the idea.

I would recommend verifying this using a program that can monitor your CPU temperature such as HWInfo or SpeedFan. Normal CPU temperatures should be below 80'c while loaded and 50'c or lower while idle.

If it is indeed overheating, then by the symptoms you would have to disassemble your laptop and inspect the cooling assembly for proper contact.

  • 1
    Actually, the first step is to inspect the cooling assembly for excess dust buildup. Dust-clogged cooling fins are a far more common problem (and one that's easier to fix) than improper contact.
    – Mark
    Aug 5, 2015 at 21:49
  • In Linux you can override the crippled cpu speed with the following commands: # echo 1 > /sys/module/processor/parameters/ignore_ppc; echo -n 2100000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq (where 2100000 represent the max speed of your cpu). I have to do this when my cpu exceeds 104C. Aug 6, 2015 at 0:50
  • @Mark: Dust build-up and clogged fans/fins is possible but would not cause the fans to run at full speed or the CPU to be stuck at minimum speed all the time. It would normally take a few minutes to warm up during which the CPU and fans would be operating at a normal speed.
    – qasdfdsaq
    Aug 6, 2015 at 11:42

If a laptop's CPU is being throttled to under 1GHz (usually in the range of ~700MHz to ~900MHz) when an AC adapter is used, but not while using the battery, it's likely being caused by normal wear and tear usage damage from either the Power Supply ID wire and/or the PSID pin on the DC jack. The PSID wire itself is a small gauge wire prone to breakage through the normal plugging/unplugging action of the power jack.

  • While OEMs place a PSID chip in their power supplies and communication protocols within the motherboard to prevent a user from using a power supply that doesn't deliver enough wattage, more often than not the intermediary components (small gauge PSID wire and/or fragile DC jack PSID pin) frequently fail from regular usage within a relatively short period of time (months to a couple of years), and I'm not aware of any OEMs allowing a user to disable the PSID functionality in the BIOS/UEFI firmware (alleviating this issue altogether).

There are only 2 solutions for this:

  1. Not cost-effective and will need to be done more than once:
    • If it's the PSID wire within the power supply cable that connects to the laptop, the power supply must be replaced
      • When the wire first starts to fail, lightly wiggling and/or pressing the power jack up, down, left, or right while plugged into the DC jack can result in the CPU returning to normal operation due to contact being made with the DC jack's PSID pin
    • If it's the DC jack's PSID pin, the DC jack must be replaced either under warranty [new motherboard] or the correct PCB DC jack must be purchased and installed (old one de-soldered, new one soldered on) by an electronics repair company (such as UBreakIFix)
  2. Permanent, cost-effective, and only needing to be performed once, bypassing the PSID's DC jack pin altogether
    • PSID chip must be de-soldered from the power supply's PCB, configured the exact way it was on the board (e.g. likely with a diode across some of the pins and a resistor coming off one), then the leads soldered to the correct pins on the motherboard's PCB DC jack.
      • The instructions on how to do so for a Dell/Alienware power brick and motherboard is covered here, however for any other manufacturer, the correct PSID chip must be identified on the power supply's PCB and it's required components identified (diode and resistor, along with their respective values) and tested via a multimeter.

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