CPU usage goes to 100%, computer becomes very slow and crashes occasionally

My desktop computer is not running as well as I would like it to. I have tried scanning for vira with avira and malwarebytes and I believe all drivers are up to date.
The strange thing is that it worked perfectly for a whole day then suddenly went back to its current state with way too high cpu usage and working very slowly.

These are my specs:

Motherboard: ASUS P8Z77 V LX
CPU: Intel i5-2400 @ 3.10 GHz (4 cores)
Memory: 16 gb RAM
Graphics: NVIDIA GTX 750 ti
PSU: be quiet! system power 7 - 400w

I was wondering if maybe 400 W isn't quite enough for this build, even though the graphics card says it will run on 300 W as a minimum. Any ideas?
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More about cpu usage 100 computer slow crashes occasionally
  1. free antivirus does nothing... just buy a good antivirus like kaspersky and scan the whole system

    if you dont have money then do a system restore
  2. thew93 said:
    My desktop computer is not running as well as I would like it to. I have tried scanning for vira with avira and malwarebytes and I believe all drivers are up to date.
    The strange thing is that it worked perfectly for a whole day then suddenly went back to its current state with way too high cpu usage and working very slowly.

    These are my specs:

    Motherboard: ASUS P8Z77 V LX
    CPU: Intel i5-2400 @ 3.10 GHz (4 cores)
    Memory: 16 gb RAM
    Graphics: NVIDIA GTX 750 ti
    PSU: be quiet! system power 7 - 400w

    I was wondering if maybe 400 W isn't quite enough for this build, even though the graphics card says it will run on 300 W as a minimum. Any ideas?


    Virus is the main cause for high cpu usage even when you have nothing running. I'm not sure about a power supply causing this but it is most unlikely.
    I suggest do the following:

    1. Download AVG Anti Virus Free version
    2. Restart your computer and press "F8" during bootup.
    3. Choose "Safe Mode".
    4. When you get to your desktop -> install AVG
    5. Restart system after installation
    6. Scan computer (not in safe mode)

    If there are any viruses then AVG will definitely catch them. Let me know how that works.
  3. Avg free and malware bytes anti malware do well and both those are free. Norton costs money and I wouldn't use it even if it were free. Cost of av software doesn't always mean it's better. It depends on your os. You may want to open task manager and look at your processes to determine which one is hogging your cpu. Make sure to click "show processes from all users" at the bottom left (assuming win7). Sometimes it's a system issue with things like svchost.dll and not a virus at all.

    Having a low output power supply may cause you other issues but has nothing to do with the cpu being maxed out. You have a program or corrupt file, be it a virus, malware, flawed system file or a corrupt file in an application like a browser.
  4. It ended up crashing when running AVG scanning, so I decided to reinstall Windows, which I am doing right now. Thank you for all your suggestions.
  5. Go to start menu, type msconfig.exe, open it and go to the startup tab, see if there is anything suspuicious there.
  6. After a fresh install of Windows, it worked fine... for a couple of days. Then it startet again, cpu usage = 100 % a lot of the time. I did a fresh install of Windows again, but this time it was like that from the beginning. I am pretty sure it is'nt a virus or drivers, could it possibly be something else?
  7. i suggest you to install some other copy of windows.... since the one you pirated is giving you issues
  8. I have tried different copies and the problem remains. I have checked msconfig.exe, and I don't see anything that I deem suspicious.
    It seems to me that it must be a hardware problem. Maybe the processor?
  9. thew93 said:
    I have tried different copies and the problem remains. I have checked msconfig.exe, and I don't see anything that I deem suspicious.
    It seems to me that it must be a hardware problem. Maybe the processor?


    nope, its the os for sure... just buy a genuine copy of windows
  10. Even genuine copies of windows have issues. There's mention of it going years back with svchost.exe using 100% of the cpu cycles. Not saying this is the case here, since there are many possibilities. In some cases it was a glitch with windows automatic update, on legit windows installs. Like any software, windows is prone to goof up.

    My suggestion would be to open task manager, go to processes tab, make sure to click the check box at the lower left that says 'show processes from all users' - the list without checking that only shows a portion of the processes actually running and the culprit may not show up. Then look at your cpu column. Maybe even click on 'cpu' so it resorts the list from highest to lowest usage (just be aware that as different processes use different amounts of cpu this will cause the list to jump around and constantly resort itself).
  11. I did as you suggested synphul, but nothing suspicious comes up. Just the normal processes using way more cpu than they should. I'll try with a genuine windows version and let you know.
  12. I tried installing a non-pirated version of Windows (just skipped the authorization for now) and the problem is still there. Any more ideas?

    Also, I tried disabling Intel Speedstep Technology in BIOS, as someone recommended this in another thread, and this seems to help somewhat, but the cpu usage still goes to 100 % and stays there, just for a little shorter time than before. anything else that maybe should be modified in BIOS?
  13. You can try booting in safe mode and see what that does. If it's still high usage in safe mode, you definitely have an odd problem. Safe mode disables most drivers and extras and just runs the os with the bare minimum and hardly any windows services started. If it acts normal in safe mode, then some service or auto run program in regular boot is hanging up. That's what I'd do.
  14. Ok, so it was once again going well for a couple of days and suddenly - I could litterally see the moment it went bad - everything is running slow, cpu usage stays on around 90-100 % and the pc shuts down after 2 or 3 minutes. I booted in safe mode and tried running AVG scan. The problem remains the same. I am thinking now that I need to take it to a shop and let them figure out what to do...
  15. I figured it out! Read a thread about thermal paste, which I didn't know about before, and it turns out my cpu really needed some new paste. After cleaning the old paste off and applying new paste, the problem seems to have completely vanished. Thank you all for your suggestions, and if anyone has a similar problem please check your thermal paste!!
  16. That's really strange. I'm glad your issue seems to be resolved but still scratching my head as to why thermal paste solved the problem. All thermal paste would do is lower thermals, it has nothing to do with processes accessing the cpu and causing its' usage to go up. So it would fix an overheat problem yes, but a running problem, I don't think so. Hopefully the problem stays away. Best not to look a gift horse in the mouth.
  17. high thermal temps would crash to save the system from burning up
  18. thew93 said:
    My desktop computer is not running as well as I would like it to. I have tried scanning for vira with avira and malwarebytes and I believe all drivers are up to date.
    The strange thing is that it worked perfectly for a whole day then suddenly went back to its current state with way too high cpu usage and working very slowly.

    These are my specs:

    Motherboard: ASUS P8Z77 V LX
    CPU: Intel i5-2400 @ 3.10 GHz (4 cores)
    Memory: 16 gb RAM
    Graphics: NVIDIA GTX 750 ti
    PSU: be quiet! system power 7 - 400w

    I was wondering if maybe 400 W isn't quite enough for this build, even though the graphics card says it will run on 300 W as a minimum. Any ideas?

    i have the same motherboard and the same problem the problem is the moatherboard change the motherboardand you will be fine
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