Lionsmike, your answer is one of the few that really focuses on the best way to start identifying the problem. Identifying the process that is causing the high CPU time is the only right first step in solving the problem.
waytron's answer, voted the best a/o 2/26, mentions this in step 5, but many of waytron's other suggested steps are steps that are very unlikely to be of use, and would only be considered as a last resort. E.g., disconnecting peripherals, updating drivers, updating BIOS, etc. might be useful only in far less than 1% of the situations that have a high CPU time problem.
The biggest "automatic" user of CPU time on my system is Norton 360. It seems to do periodic small checks of some sort in background that eat up a lot of CPU time and can't be cancelled. And Norton 360, unlike Norton Anti-Virus, uses a lot of CPU time briefly for every web page you go to. If I knew for certain that a different anti-virus program was less likely to hog my system when I didn't want it to, I would move to it immediately, but that's not something covered in the reviews.
If Norton put a simple check in its programs to keep its share of CPU usage at a maximum of 40%, millions of users would be much happier. If anyone knows of an anti-virus program smart enough to limit its CPU usage, I'd love to know of it.
A number of people mentioned a CPU usage problem if a system has been off for for than a week or so. That's very true. I have an old backup system that I only use every few months, and when I turn it on it takes a LONG time for it to complete all the updates it wants to do.
The big problem with high CPU usage on my laptop is that it causes the laptop to overheat and shut down unless I open it up and dust it out myself every six months or so. I use a free program called SpeedFan to monitor the internal temperatures, and it has been very useful.
The other two top answers, by NoxTheOx and PBaker2, do correctly address finding the culprit process, but are short on the description of what to do about it. The process may be one that doesn't allow you to cancel it, such as many anti-virus processes that are very efficient at hogging CPU resources. It may be a virus. It may be something else. It may be a task started at startup that you can prevent from starting by using MSCONFIG.
Being short of memory does not affect CPU usage by more than 2-3%, but being short of memory does slow down your system dramatically by forcing swapping of real memory into and out of virtual memory on disk. The extra CPU time required for the swapping is very small, but the clock (user) time required for all this disk swapping is very high.
Heavy CPU usage will cause your system to run much hotter, but running hot does not increase your CPU usage.
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General discussion
CPU keeps going to 100%--any suggestions to remedy?
Hi, I'm running Windows XP Pro SP2 and I have developed a
problem where by the CPU keeps going to 100% and either
freezes the PC or slows it down to virtually standstill. I
have searched on the net and found that quite a few people
have this problem. I tried some of the fixes suggested, but
they didn't work. I have to reboot the PC and then it?s fine
for awhile. What could possibly be causing this problem? Is
this a problem with the operating system or is it a hardware
problem? I hope you can help with this problem. Cheers!
--Submitted by Anthony K.
Answer voted most helpful by the CNET Community newsletter readers:
CPU Usage Stuck at 100%
There are many things that can cause a computer to show 100% when you display the CPU usage. Spyware, viruses, bad drivers or damaged programs can all lead to this type of problem. In some cases, it can be a known issue with your specific model computer, so you should first check the website for your computer to see if you see anything there regarding this issue. If not, then there are several ways to approach this problem.
1. BACKUP Your Data ? Sorry but I can never say this enough. You should never work on a computer without first backing up any critical data.
2. As mentioned above, check your manufacturer?s website for any known problems with your specific computer model.
3. System Restore ? If the problem just started within the last few days, there is always a fair chance that running a Windows System Restore and setting your computer back a few days may solve your problem. But if you have had the problem for awhile OR you have installed a bunch of programs or updates recently then this may not work at all. System Restore can be found by going to START > ALL PROGRAMS > ACCESSORIES > SYSTEM TOOLS > SYSTEM RESTORE. Note: I would not recommend going back more than a week or so.
4. Virus and Spyware ? I can only assume that you already did this but a computer that is infected with viruses and/or spyware can exhibit this type of behavior. So make sure that your computer is totally clean by running full virus and Spyware scans. You may even want to double check by running one of the many free online virus scans.
5. Identify the Process - See if you can identify a specific process that is using the most CPU percentage. Use Ctrl+Alt+Del to open task manager and click on the processes tab. Scroll down through the list for any process that has the highest CPU percentage. You can try to end that process and see if that helps and then Google the name of the process to help figure out what it is. You may luck out and find the exact program to uninstall or update to fix the problem. But, in most cases it will turn out to be one of the many generic windows processes and may not really give you any real clue as to the exact problem.
6. Disconnect Peripherals ? Shut down your computer and unplug all external devices such as Printers, Scanners and Backup Drives. Leave only your Mouse, Keyboard and Internet Connection plugged in and reboot your computer to see if the problem is still there. If the problem goes away, plug things back in, one at a time until you have isolated the problem device.
7. Shut Down Startup Items ? Use msconfig to Shut down all startup programs and reboot the computer to see if the problem goes away. If it does then go back and methodically turn back ON individual startup items until the problem returns. Once you isolate the offending program, you can Google the name of the file to find out which program it is related to. To use MSCONFIG click on START and then RUN and type msconfig in the run box and then click on OK. Click on the STARTUP tab and you will be presented with a list of items that are going to run automatically every time the computer starts. You can select or deselect any items the you want to start when your computer boots. Now click on OK and reboot your computer. You can go back anytime and run msconfig to turn back on any items that you choose until you find which one is causing your problem.
8. Update all drivers for your computer ? Go to the website for your computer and download and install the latest drivers for your computer. Start with Chipset, Video, and Sound drivers first, followed by network, modem and others.
9. Update Bios ? In some cases the Bios may need updating, but I would stay away from this unless you really know what you are doing, because you can permanently damage your computer if you mess up during this process.
10. Problematic Programs ? There are many programs that have been known to cause this type of problem. For example some earlier versions of Kodak Easy Share software had this problem. Norton and some other antivirus software can become corrupt and cause this issue as well as software and drivers associated with many All-In-One printers. You should suspect any program that calls home for updates as well as file sharing programs like kazza and limewire. Other VOIP software such as Skype can also be a problem. I would suggest uninstalling any programs that you do not need at this moment to help isolate the problem. NOTE: Do not uninstall anything you want that you do have a way to reinstall such as having the original CD?s or downloads.
11. Full Recovery or Reinstallation ? If all else fails then you may have to resort to a full system Recovery or a reinstallation of Windows. This would be a last resort, but can rejuvenate a computer to like new condition and for some problems, may even be less time consuming.
Good Luck and Please keep us posted as to what you find.
Dana
Wayland Computer
http://forums.cnet.com/5208-10149_102-0.html?forumID=7&threadID=284007&messageID=2705924#2705924
Submitted by waytron
If you have any additional suggestions or experience of your own to share with Anthony, please click the reply link and post away. Please be detailed as possible in your answers. Thank you!
Discussion is locked
31 - 60 of 339 Posts
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I moderated and worked out in the AOL antivirus help chat for years. I like everyone else heard all of the Norton hog stories. I took the time to ask a few questions and found that people who installed the Norton AV as a stand alone or as part of the System Works package did not have that cpmplaint. People who did had the complaint were almost always those who had installed Norton Internet security or 360.
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Anthony developed a problem where by the CPU keeps going to 100% and either freezes the PC or slows it down to virtually standstill.
Hi Anthony, I had a similar problem and solved it with the following actions.
1. eliminate the possibility of a hardware problem by checking your hardware device manager. ( I use the shortcut of pressing the left windows button and the pause/break key at the same time)
2. remove the cover from your computer and make sure the CPU cooling fan is working and not clogged with dust. An overheated CPU can give you that symptom.
3. If you have gotten this far, it is NOT a hardware problem. Now lets move on to Software. When your computer first boots, let everything standard load up and then press Ctrl-Alt-Del. Click on the processes tab. along the top of the process list, click on the heading CPU. This sorts the processes in use by how much they use the CPU. (you may have to click it 2x to get the high useage at the top of the window) The "System Idle Process" should be over 90% in normal working mode.
4. Drag the process window out of the way and use your computer normally. When you notice that the system is bogging down, drag your process window out and see what is causing your high activity level. Click on that process to highlight it, then click on the END PROCESS button.
5. This should improve your performance, but be aware that some processes are smart enough to restart themselves. In this event, you will see the one you just closed magically reappear. If so, a little detective work on the process name should let you know what program is using that process.
6. If you think you have found the culprit, don't just start uninstalling programs. see if you can disable it first. Many times the offending program can be found loading itself at bootup. You can see a list of these by clicking your start button, click RUN, and type MSCONFIG at the prompt. The window that opens has a tab called STARTUP. Look through the list and see if you can find your offender there. if so, just uncheck the box(s) next to what you want to disable on your next reboot.
7. If you can not find an offending program that YOU installed, you should run a Spyware checker (Spybot is one of my faves) After you clean up your spyware... empty your cookies, and delete your temporary internet files (internet explorer, tools, internet options.)
8. 9. & 10...couldn't think of anything more to tell ya other than you are not alone, it is fixable, and you WILL get to the bottom of it all.
When I had this problem the offender was McAfee SPAMchecker. Although I have a great respect for their virus protection, their e-mail spam protection drove my system NUTS! We were having rolling brown-outs from the power company and that program would glitch into an endless loop. I used the above items and disabled the program. problem solved.
Cheers to you mate!
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I had this problem recently. My PC is 7 years old 1.8 GHZ and 512 Ram Win XP SP2. After trying all the normal things that are suggested in the answers in the FORUM, at the suggestion of a friend I removed the cover and did a complete dusting of all the boards and heat sinks and the fan and all the openings. In the hard to reach places I used a soft bristled paint brush to move the dust to a place where I could vacuum it. After this was done my PC now is performing as if new. The CPU usage drops to 4% to 24 % most of the time. Before it was almost always pinned at 100%.
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As mentioned in many of the responses, identify the offending process. Rather than deleting the process, right click it, and select "Set Priority", and move the priority down to Below Normal or Low. THEN Google the process name and determine whether it is some sort of malware.
With Spybot, you can remove items from system startup.
***Back up your registry! Spybot can do this for you as well.***
In the menu, select Mode, Advanced Mode. Then select Tools, System Startup. A list of active processes will appear. The ones shaded RED are known to be spyware. At the very least, un-check them. I delete them. The Yellow-shaded processes are worth considering, but check them carefully--some should be left checked.
After carefully reviewing these processes, reboot. Use spybot to check them again. If one that you had unchecked came back anyway, it may be spyware or a virus. One process, ctfmon.exe in the Windows\system32 directory, will be reinstalled by Microsoft. If you have an instance of ctfmon.exe located in another directory, it should be removed.
If the offending process (as identified with the tack manager) is one of those disabled from startup, this should resolve the problem.
jbelcherpc
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You taught me a shortcut I didn't know! (Menu+Pause)
Hah! Just had to laugh at what I wrote. 
If your computer is giving you a problem, maybe you need to check it for menupause. Lame, I know, but almost related.
Thanks for that tip. I'll bet it works with Win98 also. I'm having a fit right now with a laptop that I'd throw away if it were mine. That may save me a lot of time.
Thanks again! (Now to read the rest of your reply.)
Regards,
Chuck
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In what program ? Windows ?
what does it do ?
I didn't see it mentioned in the post you refered too 
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I read the other 2 of the top 3 responses and I can't believe your running third in the most popular answer!
I'm an engineer and I cannot believe the other posts first steps! Always eliminate the easy things first.
I had a major problem a year ago with my VGN-SZ120P that Sony could not fix. Tried the Scan, System Restore, Re-install the operating system from behind the partition- all failed.
Sony then sent out recovery disks... Reloaded the operating system, same problem!
Called for a tow [return box] then called my brother who is a certified MS professional. He said, look in Task Manager, Processes, click CPU twice... If System Idle Process isn't at the top of your list [mine was 3%], turn your PC off and shot some compressed air through the air exhaust... I had a dust bowl come out! Restarted the machine... Ran fine. My System Idle Process was 97%!!!
I'm convinced it is Anthony K.'s problem because of one statement, "...and then it's fine for awhile." Duh, overheating!!!
This is my first CNET forums post so I don't know if I'm doing this correctly but far too many people rope their machine when it's something simple...
If you are practicing safe sex (i.e., virus scanning, spyware gecleaning, nicht gefinger poken, firefox, no download from uncertain parties) try the process of elimination first, you can always do the lobotomy later!
eol,
Germannator
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Duh wasn't called for and definitely isn't right.
it's like DUH there can only be one possibility, and that is not true.
(and then it's fine for awhile." Duh, overheating!!!)
I'm not going to give all the reasons this "COULD" easily refer to but.
Flash, and older computer or low ram that are left on or have a few to many programs and or windows open are absolute definite possibilites.
aside from the scvhost, USB, confilicting this or that, malware, spyware, virii etc etc.
Defitnitely clean and blow or vacuum that thing out, if you haven't done it, or live where there's alot fo dust or animal hair Etc.
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Hi Germannator,
You mention that you have VGN-SZ120P and that sony sent out recovery disks once. I have the same model, but have lost my recovery disks. Sony has stopped supporting this model. They say I can get it from another SZ120P owner, install the image.
Would you be able to send me the disks?
Sorry for requesting you out of the blue, I really don't have too many options.
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Hi,
I have the same problem than you. I would like to know if you or anyone else have the recovery disks for the VGN-SZ120P because disks are damage.
And if you do, would you be able to send them to me?
I Would really appresiate it...
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Anthony,
To fix your problem do one of the following:
1) If too many start up progams slow you down:
Start/Run/msconfig/startup/uncheck programs you do not want to start then restart computer
2) Alternatively.....:
control-alt-delete to get task manager...then...
go to processes and eliminate those processes that run in the background (see processlibrary.com to distinguish which processes are unneccesary)...there are quite a few...
Finally.....
3)Change the page file size to about 789 MB
Start/Control Panel/System/System Properties/Advanced/Performance- Options page/Virtual Memory/Change/Virtual Memory Page/Set custom value to 789 Mb max/set/RESTART/apply/ok
This should speed you up especially after you use your "Disk Cleaner" from Freeware at www.webattack.com and...
"Jk Defrag 3.16" from the same webattack.com website
Best wishes and quick running
Jesse Jr.
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I loved it when you said.
"This is easy".
It sounds like you are saying fixing the problem is easy.
But if you think that is a definite fix or solution you have about hundred other things comin.
On ther other hand if what you're refering to as easy is turning off
Startup programs in the manner you stated, that is easy!.
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SOUNDS LIKE YOU HAVE STUFF RUNNING IN THE BACKGROUND ON YOUR START UP
YOU NEED TO START WITH FINDING WHAT PROCCESS ARE RUNNING AND WHAT YOU WANT RUNNING AT STARTUP.
GO TO YOUR STARTUP-RUN AND TYPE IN MSCONFIA WINDOW WILL POP UP.
GO TO START UP TAB SEE WHAT IS RUNNING.
UN CHECK STUFF YOU DO NOT WANT TO HAVE RUNNING BUT BECAREFUL
YOU COULD STOP SOMETHING YOU NEED.
AND IT WILL ONLY TAKE EFFECT AFTER RESTART.
AND RETEST.
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Microsoft has two great utilities you can download and install which will help you identify offending runaway processes. Once you have identified the offending program by seeing the cpu time being used or the file access activity, you can then do a search on Google to find help in dealing with the resource hog.
Process Monitor, can be downloaded from here. http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx This program monitors file access and well help you identify programs that are constantly accessing your hard drive. If you don't know anything about the identified program, just Google it.
Process Explorer will show you all the process that are running on your system, and how much memory and CPU time they are using, and the process tree they belong to. Is much better at identifying runaway programs than Task Manager. Process Explorer can be downloaded from here:
http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx
This works for me. First I found that Symantec Endpoint Protection was way more of a cpu and file access hog than I bargained for, so I gave it the Ax. Then I found the indexing process was running even though I was using the computer. It was suppose to index only when I was not using the computer. But on system with very fast CPUs like mine it just churns the hard drive anyway. The constant drive noise was bothering me so I axed it to.
Now my system works very nicely, hard drive noise and now I am using free AVG antivirus without any problems, instead of the 300 dollar Endpoint Protection that slowed everything down.
Without these two utilites it would have been nearly impossible to detect the programs causing these problems.
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I think we all know that something is running in the background to cause the cpu to run like that. A hardware problem can cause this also if the cpu is over heating. Try different Spyware software. I had a embedded program that would not come out until I ran XoftSpy. The same with Registry Cleaners. I think the best diognstic is to run MSCONFIG from run and see what items are in the startup. Deselect them all and try one at a time. Good Luck
Wimpy Johnson
wimpy@valornet.com
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I have had that problem before and the thing that did it for me was switching some of the BIOS settings. Now I also heard that the problem cannot be remedied except in the case of total reformat but I'm sure you are not looking to do that so try a few things like msconfig through the run function and stop alot of the programs from starting up which will cause the CPU to go to 100% in no time. Also look at the processes under the windows task manager and look to see what program(s) is causing so much processing time and deal with it immediately before it takes over and locks it all up. When you find the process causing all the problems then right click it and choose set affinity to 1 CPU core if you are running a dual core processor, this will help you immensely. That will at very leasy buy you some time to find another way of dealing with the problem. I do know that there are viruses that use 100% processor time but I'm not sure how long it goes on for. This is fixable because you said that it goes back to normal after a reboot. I have an AMD athlon dual core and AMD does have a small program that manages the processor and I'm sure that Intel has a similar program for their processors. I hope this helps you out. Good luck
Matt
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Well, my first reaction to this post was, "Windows, at it again!" But then I remembered the same thing happening to my computer and a friend's, and the problem turned out to be Norton Antivirus. Nasty program, that. It can easily eat up a lot of computing power.
Me, I switched to Linux, Ubuntu version. My CPU runs with far less heat and stress than it ever did in Win XPsp2.
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I DO NO USE IT OR McCAFEE AVG FREE IS BETTER AND LEAVE YOUR COMPUTER RUNNING ITS HARD ON IT TO RESTART ALL THE TIME
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You might want to get your keyboard looked at.
It looks as though the Caps Lock key is stuck in the On position.
Posting in all Caps is the forum equivalent of shouting and is considered rude and obnoxious.
Please check the Caps Lock before you post again, we know you do not shout deliberately.
Thanks
P
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Mine was. Badly. finally I got an automatic shut down for "overheating". Took the thing apart an blew the dust out of it and off the chip and lo and behold she's a runnin' just like new again!!
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I had a problem like this once. I had a virus that lived in a temporary folder (a windows temporary, I forget which one exactly) It opened a second instance of svchost.exe, which started some sort of a conflict with the legitimate svchost. So check your running processes (ctr+alt+del) and see which process is taking up so much cpu time. Then take the name to google...you may find your solution there. (for me that involved simply emptying out my temporary folders). Hope this helps.
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This, by itself, is not necessarily a fault - programs that are complex and/or are handling large amounts of data may periodically utilize as much processor time as is available. But it is a problem if it locks up or drastically slows the computer down. I experienced this problem last year after I installed a spyware removal program called Prevx. It was great at cleaning up a nasty virus I had, but for the next few weeks I experienced all the problems you are having. I found other reports of this problem with Prevx on the net so uninstalled it and all was well from then on.
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I have this problem once in a while, but it *seems* to be right after Norton does an update, and the files are decompressing or doing their magic. If you wait long enough, the slowness goes away but yes a reboot also helps. Also, if I could figure out how to get Norton to update at 2:00AM rather than the middle of the work day, it would be better.
Mysteriously going to 100% might also mean there's something running that maybe you don't realize. Check your task manager and also, get rid of any unnecessary junk that windows likes to run from startup. All that stuff running unnecessarily is a waste of electrons and can bog your system down. 100% is not good, however. Are you sure nobody got through your firewall?
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I've had this problem earlier in the year. What it turned out to be was a 'memory leak' with windows XP PRO - I wound up reformatting from scratch. I hope someone has a better idea for you.
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Memory leak!! I have not heard that since service pack 1. There was a memory leak problem in the beta which was believed to have been resolved prior to the release, and then it showed up in the released version of XP but service pack 1 was suposed to have taken care of it. I have not heard of that for so long that I forgotten about it.
Were you fully up to date in your OS and MS Office. I believe that having office installed was involved with the leak.
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Mr. Anthony,
Usually this problem happens with, if you have USED AND INSTALLED PIRATED OPERATING SYSTEM.
If this is the case then the answer is understood. Spend some money and get fresh copy of OS.
All the best.
shewak@gmail.com
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I'm assuming you running a pretty clean setup and no application is running out of control . Bring up the task manager and look at the current task. (CNTR_ALT_DEL then select task manager..Looks for a single process running at 100%. you may need to do some things. If you find the process, kill it. Find the application that is causing the problems and upgrade/report it.
If no application is causing the slow down, be sure to check for adware, spyware, and such, Mcafee and other software here can help. Unplug your computer from the INternet, and/or LAN all together. Some bots/virus might stop here.
Check your hard drive, it may be going. the swap file may be bad, or a lot of read errors on it. Run some hardware diags on it.
If you still have the problem, no virus, no spyware, no task running at 100%. YOur harddrive has room and has to read or write errors. Upgrade your drivers.
Upgrade your drivers for your video card first and then sound.
If this fails start to yank hardware. Unplug the Ether net card first. Then any other cards you have, Which probably won't be any more...
Hope that helps...The windows slow downs can come from anywhere.
After years of building PC from the 8088 days and the Intel 386 until now. I finally bought a b MAC.
Within 3 months on my first mac I had two more.
I have had a single problem like the one your describing every since...heeh
Get a MAC you will love your computer again...
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Hi Anthony
I had the same problem. I bought more RAM but that didn't work so I opened up the computer and found that the heat sync had detached itself from the motherboard and my processor was getting hot as soon as I turned on the computer, causing it to immediately freeze up. Luckily, it didn't burn out, which often happens most of the time, I was later told. So, check your heat sync to see if it's loose or detached. After I got it reattached to the motherboard, my computer works perfectly.
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