Old XP computers are slowing down because their memory is being outgrown


There are still a lot of old computers out there running Windows XP.  Many of them are slowing down and their owners are not happy with the poor performance.  Programs take too long to load and are slow to run.  The computer takes forever to boot up.

This poor performance is usually due to not enough memory.  What was adequate memory when the PC was purchased is no longer adequate memory for the demands of present day computing.  Over time the computer owner has added programs and the programs themselves have grown larger.   Now the memory gets filled and performance tanks.  The computer’s RAM memory has been outgrown.

When windows has adequate memory to hold all the programs it runs well.  When windows runs low on memory it must manage its memory and this REALLY slows down the PC.

The best fix is to add more physical RAM memory.  Some performance can be recovered by removing programs from being loaded at startup.  A new PC with adequate resources also works.

Technical discussion

Windows XP debuted in October 2001.  Back then memory was expensive so skimping on memory was a cost saving measure used by manufacturers to keep PC prices low.  Many early and low end PCs had 128, 256, 384 or 512 MB of RAM installed.  The Microsoft system requirements for XP Home are “At least 64 megabytes (MB) of RAM (128 MB is recommended).”  Wow, this is really inadequate.

Back in the day these computers ran OK because the programs they ran weren’t so big and the amount of memory was adequate to run windows, a browser and a few more programs.

Over the years the size and number of programs have increased.  Windows itself has grown with service packs and updates.  Browsers have increased in size with new features like Flash, tool bars, add ins and browser helper objects.  Now we need antivirus programs and their malware signature database grows daily.  Printers add programs and updaters.  iTunes adds QuickTime, updaters and more.  Programs grow in size as new features are added.  New programs are added to the computer.  All these programs use memory when they are run.  Some of these programs install components that run at startup and add to the memory use burden.

For example, when the PC was purchased it ran the programs of the day well.  Imagine the PC had 512 MB of RAM memory and the programs of the day – windows, Internet Explorer and a few other programs – only took up say 50% of that memory.  Now imagine that same PC with the same 512 MB of RAM memory.  Now it is asked to run more programs and the programs have grown in size – windows, IE, Firefox, antivirus, printer programs, iTunes, audio and video programs, Flash, Adobe Acrobat, CD and DVD utilities and other programs.  Now the memory gets say 90% filled.

All these new and larger programs outgrow the computer’s memory.  Now the PC’s memory is no longer adequate, and gets filled up.  When windows runs low on memory it must actively manage its memory and this kills performance.  To make room for new programs in memory, windows must remove from memory programs that were not recently used and write them to disk.  This memory management operation of writing old data to disk (to pagefile.sys) is called paging and is a “slow” operation.   This makes the computer slow.  Excessive memory management, writing and reading memory to and from the hard drive, is also called “thrashing.”  The symptoms of paging are slow performance and excessive hard disk activity (hard disk light flashing).

A simple way to check how much memory Windows XP has and is in use is by using the Windows Task Manager.  (Start the Task Manager by pressing <Ctrl><Alt><Del> and select Task Manager or press <Ctrl><Shift><Esc>)  Select the Performance tab and view the Physical Memory data:  Total, Available, System Cache.  If the Available and Cache numbers are low, like less than 20% of Total, this PC is lacking adequate RAM memory.

Windows Task Manager
This PC has inadequate memory to function well. This PC has only 256 MB of RAM. Note the Available memory is low and cpu use is high.

To find out what programs are using memory, in Windows Task Manager, select the Processes tab and click on the Memory Usage column header to sort the list by Memory Usage (and check the Show processes from all users box).


Windows Task Manager, Processes tab
Windows XP with 256MB RAM, running IE, Acrobat Reader, MS Paint, file explorer and AVG Antivirus.

The best fix is to add more physical RAM memory but some memory space and performance can be recovered by removing programs from being loaded at startup.


To add RAM to a PC it is best to consult with the manual for what type and how much RAM the PC takes.   Then find out what RAM is already installed by opening up the PC or running a system / memory enumeration utility.  PCs typically have 2 or 4 slots for RAM.   Memory can be a little voodoo about what works, it is best to match speed and type but odd combinations may work.  Funny that older type of memory is more expensive than new type memory.  $40 per GB is typical for older RAM.

I recommend at least 1 GB RAM (1024 MB) these days for a Windows XP PC.   Note that 32 bit windows cannot utilize more than about 3.5 GB RAM.

DDR RAM memory module
DDR RAM memory module


Another approach to rectify memory issues it to remove programs from startup.  Some programs automatically load into memory when the PC boots by way of the Startup folder or a registry entry.   Some of these programs are not necessary or wanted and can be stopped from automatically loading into memory and run.  Programs like an instant messenger client or Skype can be set not to run at startup in their program options.  Some software loads a program to monitor for updates like HP printers and Apple software.    Uninstalling unused applications may also save memory.   Unused browser tool bars are good candidates to uninstall.

To see what is installed/run at startup, start up the System Configuration utility which is also called msconfig (start, run, cmd, msconfig).  Uncheck what you don’t want to start up.  When making decisions about processes to start or not, consult processlibrary.com or a search engine to find out what it does.  Make a system restore point first so you can easily recover from a mistake!  Don’t block the start of windows processes like lsass.exe, svchost.exe, spoolsv.exe and csrss.exe.  Candidate programs to disable at startup are audio control panels, messengers, file sharing programs, update checking programs, audio/video and things you don’t want or use.  Examples are:  HP Software Update, MS Office OneNote, Windows Sidebar, Real Player, Winamp, YahooMessenger.exe, OpenOffice, CD/DVD packet writing utility, etc.

Some programs can be disabled in their preferences:  QuickTime updater (qttask.exe), Skype, Yahoo IM, etc .

A note about files and disks.  Deleting temporary files and the Internet temporary files (cache) of browers can speed up a PC.  If you don’t manually periodically delete these files, configure your browser to automatically delete them on exiting.  A hard disk that is too full or fragmented can slow down a PC.  Free up space on your disk and defrag if necessary.  Hard disk errors can slow down a PC.  Run the Check Disk utility (fix file system errors and scan for bad sectors).


When XP was released, Oct 2001, typical computers had a Pentium 4 cpu, DDR memory, IDE hard disks, IE6.

Computer slowness can be due to other factors:  slow cpu, memory, busses, 5400 rpm hard disk, hard disk problems (excess number of temporary files, disk full, fragmentation, file system problems, disk sector errors), slow video processor/card and malware.

If someone uses a modern fast computer then uses an old computer, the perception will be this old one is slow but may be working normally.

Antivirus programs can slow down a PC when downloading updates and scanning.  This can be an issue when PCs that are not on 24/7 are booted and realize they have not updated or scanned and kick off those activities.

Always good to make backups.  Before working on a PC and in general.  Registry.  System Restore.  Data.  Disk.

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