Why is my CPU intermittently slow?


My home computer will slow down considerably while it is running. After a slow period of 1-3 minutes, it will speed up to its normal speed. While it is slow, it can take several seconds to paint a screen, and the mouse pointer will become uncontrollable. Then after awhile as stated, everything will run just fine.

I have replaced the video driver, then I put in a new video card. Then I replaced the power pack, but I still have the problem.

The real mystery happens when I take the CPU to another location, not in my home. When I do that, the computer runs just fine all of the time. This made me think that I was having a power problem at home, so I plugged a volt meter into the wall, and the voltage was within specs for over a half hour, 114.5 to 116 volts. I even tried plugging into different wall circuits, and had the same problems.

Now I'm at my wits end, I don't know where to turn, or even what to look for. Please help.


This question was answered on January 10, 2003. Much of the information contained herein may have changed since posting.

Assuming your hard drive is not close to being full, and being sympathitic with the mind games intermittent problems can cause, consider the following:

Let's begin with that AMD Processor Overspec'd (some say "overclocked") right from birth, those processors, though giving plenty of bang for the buck, certainly do need lots of fresh air.

Good heat sink, good heat coupling (replace if ever the heat sink is removed for any reason), good fan, plenty of airflow, and a dust free environment are all necessary for good performance Consider installing an auxiliary case fan, if you have the cutouts for one Such fans go for about five bucks, and are well worth it.

Make sure the ribbon cables for the hard and floppy drives do not form a wall that impedes airflow through the case Those new round drive cables might be in order, or at least a redressing of drive cables away from the processor.

This is your most likely problem, but I am in an ambitious mood, so allow me to continue.

Next, I have to ask if you are perhaps running a home network Connecting to a bad network node can cause difficulties, as the network card will want to retransmit and request information that it finds questionable due to network noise.

Next, consider the modem It, too, will act in a similar manner Noisy phone lines, bad or intermittent patch cables, or in the case of my home, gophers with a penchant for travel and an appetite for wire insulation can make for bad lines.

Wireless network? Even worse Rearrange all the furniture and tear out the plumbing, as necessary.

Is the CPU standing upright on a stable surface? Bad CD drives will slow a computer to a crawl I relegated one CPU to the bone pile pending discovery of a bad CR-ROM drive once Took me weeks, and a sentimental obsession for the old Pentium to finally figure it out Anyway, CPU position can affect the workings of such a drive.

If nothing else works, best thing to do is begin unplugging stuff Unplug the CD drive Unplug the modem, circuit card and all (careful, Windows might insist on reinstalling the thing, so have drivers available) Network card, if applicable and any other non-necessary expansion cards.

Obviously, you’ll have to leave the monitor, hard drive, power supply, video card and keyboard intact, but I am certain you will zero in on the problem.


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Posted by Robert of Mesa Community College on January 10, 2003