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How To Diagnose a Suddenly Slow Windows Computer? 835

Posted by timothy
from the ineffably-inexplicable dept.
Ensign Taco writes "I'm sure nearly every one of us has had it happen. All of a sudden your Windows PC slows to a crawl for no apparent reason. Yeah, we all like Linux because it doesn't do annoying things like this, but the Windows desktop still reigns supreme in most managed LAN work environments. I'm running XP with 4G of RAM and a decent CPU, and everything was fine, until one day — it wasn't. I've run spybot, antivirus, and looked at proc explorer — no luck. There is no one offending, obvious process. It seems every process decides to spike at once at random intervals. So I'm wondering if there's a few wizards out there that know what to look at. Could this be a very clever virus that doesn't run as a process? Or could this just be some random application error that's causing bad behavior? I've encountered this a few times with Windows PCs, but the solution has always been to just add more hardware. Has anyone ever successfully diagnosed this kind of issue?" And whether such a problem is related to malware or not, what steps would you take next?
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How To Diagnose a Suddenly Slow Windows Computer?

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  • PerfLogs (Score:5, Insightful)

    by Drakin020 (980931) on Thursday January 22, 2009 @06:11PM (#26566651)
    Run performance counters against the computer to see what might be spiking. (Hard drive usage, memory pages /sec etc...)
  • Virtual Machine (Score:5, Insightful)

    by DissociativeBehavior (1397503) on Thursday January 22, 2009 @06:13PM (#26566687)
    Watch porn in a virtual machine.
  • by GPLDAN (732269) on Thursday January 22, 2009 @06:22PM (#26566863)
    Between DiskMon, FileMon and Process Explorer - there should be nothing that you cannot see. The new generation of viruses that steal thread handlers from other processes are nasty, but very very hard to detect.

    Add in wireshark, as the cause of many a slow computer has been a ISP provided DNS server that has suddenly decided to take it's sweet ass time about answering queries for A and PTR records. Usually a by-product of being under some external load that you know nothing about (it could be backing up, etc).

    DiskMon in particular will show you any files that are being sought by any process, an incredibly valuable resource.

    Every workstation in our company has the SysInternals complete suite installed in the C: drive. The help desk has been trained to use it. It solves alot of problems.
  • Updates (Score:3, Insightful)

    by Thelasko (1196535) on Thursday January 22, 2009 @06:23PM (#26566889) Journal
    Unfortunately, software companies all tend to schedule their updates to download/install at about the same time. Perhaps your anti-virus software, or even Windows itself, is running a live-update.
  • by citylivin (1250770) on Thursday January 22, 2009 @06:27PM (#26566957)

    slashdot: Individual personalized tech support?

    wtf kind of article is this?

    fucking take it to a shop if you cant handle reinstalling windows

  • by Jane Q. Public (1010737) on Thursday January 22, 2009 @06:29PM (#26566995)
    and somebody marked it troll??? Come on, folks, get real.
  • by pla (258480) on Thursday January 22, 2009 @06:41PM (#26567191) Journal
    slashdot: Individual personalized tech support?

    Ignoring your blatant troll, I think most of us who use Windows, whether by choice or at work, have experienced exactly what the FP author describes.

    Personally, I keep Process Explorer permanently open, and have noticed times when XP will just sit there and refuse to respond despite literally nothing using up a significant amount of CPU, RAM, or I/O. And not just for a second or two of lag, but well over a minute of completely refusing to respond. The mouse still moves, and most already-running programs will work, if somewhat sluggishly, but try to open a new program or even get a right-click menu, and you may as well go get coffee.

    If someone knows a trick to fix this, I have no doubt we'd all love to hear it.

    And for those curious, my HDD remains in DMA-5 mode, it doesn't matter whether or not I have an active network connection, the pagefile hasn't started growing rapidly, and I feel fairly confident that I have no viruses, spyware, or even any of the annoying auto-startups like Quicktime, the Java updater, or Acrotray.
  • Re:Simplest answer (Score:3, Insightful)

    by Atraxen (790188) on Thursday January 22, 2009 @06:48PM (#26567287)

    It's not a bad plan, but I'd shorten the reinstall time even further by setting up a backup image of the OS+programs after a reinstall, and park it on the RAID. Then, your time spent is limited to the transfer rate between the two drives.

    Remember your offline backups of the RAID as well though - otherwise you may simply end up with a well-preserved virus refuge.

  • Re:Check the HDD (Score:3, Insightful)

    by rew (6140) <> on Thursday January 22, 2009 @06:52PM (#26567355) Homepage

    However..... Even if SMART checks out and the vendor-test program says the HD is ok, some drives might just be taking seconds to minutes to "recover" the right data.

    If this is the case, your monitor programs would not show much disk activity, but the HD light will be continuously on during the stalls.

  • Service pack 3? (Score:3, Insightful)

    by pluther (647209) <pluther&usa,net> on Thursday January 22, 2009 @07:06PM (#26567555) Homepage

    When mine did a few weeks ago, it turned out to be because it updated itself to XP Service Pack 3.
    Removing XP3, and installing the "critical security updates" as per Microsoft's tech support document on the subject, fixed the problem and got everything working back the way it was originally.

  • Re:Simplest answer (Score:5, Insightful)

    by bluefoxlucid (723572) on Thursday January 22, 2009 @07:15PM (#26567659) Journal

    If you've got everything backed up, that should be the quickest option. (Versus spending a weekend or so digging and digging to find the problem.)

    It's Windows, not Ubuntu. Last time I had a "reinstall windows" problem, it took me 2 weeks to get all the software installed and configured again. I can't just tick off what I want and hit Apply.

  • Re:Check the HDD (Score:2, Insightful)

    by doug_hastings (864738) on Thursday January 22, 2009 @07:23PM (#26567763) Homepage Journal
    My Seagate 500g drive crippled windows as its lousy firmware bricked it, and now if its plugged in windows runs very slow if at all. An addition 2 cents worth: CCleaner and RootkitRevealer
  • by kabloom (755503) on Thursday January 22, 2009 @07:30PM (#26567857) Homepage

    I have become an expert at telling people that their computer is slow because they're using twice as much RAM as their computer has, and therefore swapping badly. I usually tell them that they need 4 times as much RAM as they have.

    I think this is not your problem.

  • by shutdown -p now (807394) on Thursday January 22, 2009 @07:31PM (#26567873) Journal

    I've seen systems start crawling on stupid windows background crap that only shows up in the process tab as "System Idle Process."

    System Idle Process cannot make system crawl by definition - it's not even a process, it's just the line that shows how much of your CPU is not being utilized at all.

    Thing is, when the system is crawling, it needs not be CPU. Random HDD reads/writes by one process can also kill performance for the entire system very fast, and yet the process will still show up as using 1-2% CPU time in Task Manager. You can change it to show the columns for I/O though and look there.

  • by AlgorithMan (937244) on Thursday January 22, 2009 @07:43PM (#26568023) Homepage
    the diagnose is: the computer has the windows
  • by DiegoBravo (324012) on Thursday January 22, 2009 @07:58PM (#26568231) Journal

    >> Yeah, we all like Linux because it doesn't do annoying things like this

    That part of the original submission is misleading/stupid (why editors didn't cut it?.) My Ubuntu 7.10 box used to crawl (well, Compiz/Nautilus/Gnome/The-UI) after several hours of continued opening/closing windows. I never did investigate the issue (because laziness) and it was fixed just with a graphical logout/login (thus, I think restarting X.)

    Remember also that a lot of Linux boxes crawl when the updatedb is executed via Cron (this is the nearest thing to Windows' antiviruses in behavior.) As the parent writes, this have to do with I/O use, despite the assigned and irrelevant "nice" priorities.

  • What? (Score:4, Insightful)

    by Yunzil (181064) on Thursday January 22, 2009 @08:07PM (#26568355) Homepage

    Yeah, we all like Linux because it doesn't do annoying things like this

    Speaking as someone who uses Linux at work every day, this is a flat-out lie.

  • Re:Check the HDD (Score:2, Insightful)

    by Anonymous Coward on Thursday January 22, 2009 @08:11PM (#26568407)

    Lastly, when you fix the issue you should remove your wife from the administrators group and just make her a user or power user. When she needs to install software or whatever just have her log in as admin.

    While it does make sense to limit administrative privileges to a minimum of capable users, preferably one, it may appear presumptuous and sexist to some for you to rattle off such a suggestion... The OP never mentioned a wife. Perhaps it is the OP's kids that don't need admin rights, or his father. Perhaps the OP is only 17 years old and has no wife or kids. Sheesh, buddy... I am a guy too with a long history working in IT. And though there are lots of males in the work force, I have met some very bright, intelligent women in my time. Sadly many of them tend not to see themselves that way after a lifetime of browbeating, some intentional and some perhaps not.

    Granted, you do suggest she can be trusted to install software and use the admin account when needed. And I will also grant that you may not have intended to be sexist there. But it is worth examining such an automatic sort of presumption in one's self. Perhaps you might have suggested the OP do the same for himself... I use a regular user account on my GNU/Linux desktop and use sudo or su to do administrative tasks. I type fast enough that it is not a real bother. Really, I feel the added step helps keep me conscious of the privileges I am using to invoke commands, in spite of myself. Pobody's Nerfect. I do hope it was not an intended slight.

    Be well,


  • imaging (Score:2, Insightful)

    by f1vlad (1253784) Works for Slashdot on Thursday January 22, 2009 @08:37PM (#26568641) Homepage Journal

    I don't use windows daily, but I have windows box for games. And what I do, to avoid having to waste endless hours investigating this sort of stuff, is maintaing fresh images of my hard drive.

    Simply keep OS and installed programs on C: drive, back up its entire image often. Something happens, wipe it and put _stable_ image over it.

    I suggest Acronis True Image Maker [].

  • by Anonymous Coward on Thursday January 22, 2009 @11:56PM (#26570221)

    The parent is correct. The difference between Linux and Windows is not that Linux doesn't slow to a crawl on occasion. No, I've seen both Linux and Windows do this. The difference (as you've demonstrated) is that when Linux slows to a crawl, you've got at least some chance at finding and fixing the cause of the slowdown.

  • by slashbart (316113) on Friday January 23, 2009 @05:05AM (#26572015) Homepage

    For the last 8 years I've pretty much only used Linux, and my experience has been that whenever the machine suddenly becomes consistently slow (not just a few seconds because of updatedb), it's a DNS issue. Maybe you have a primary DNS that times out and then fails over to a second one or so.
    That's my rule of thumb, and it has served me well.

    Probably the same on Windows.


  • Reinstall (Score:2, Insightful)

    by Dracophile (140936) on Friday January 23, 2009 @08:11AM (#26572859)
    Tweak and take an image. As soon as it starts to suck, and assuming you take backups you know about, resume the image and restore. NEXT!

Genius is ten percent inspiration and fifty percent capital gains.