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6 free tools to check the PC's memory

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The computer's memory is one of the most reliable components, but it can and does occasionally develop faults. The likelihood of a fault is the greatest when you upgrade the memory and add more or replace it completely. Then incompatibility, poorly seated memory modules and chips zapped with static can all cause strange faults in Windows or the software you use.

Sometimes it is obvious that something is wrong with the memory and the PC simply won't boot up, but it is also possible to have a situation where the the memory works and Windows starts up, but it is unreliable and then intermittent faults crop up when you are running software.

If Windows is unreliable and you are getting strange errors you should thoroughly check the computer's memory. This doesn't mean that you have to take apart the case and inspect the chips on the memory modules on the motherboard and you just need to run a memory testing and diagnostic tool.

There are several available and one is even provided with Windows 7 (at least in the Ultimate edition that's available as a beta). Memory testing utilities cannot check the PC's memory when Windows is running because the operating system needs a large chunk of it in order to work.

Testing involves writing various bit patterns to memory locations and then reading the memory to check that what is read is what was written. This would wipe out Windows, so memory test utilities are tiny programs that run in a Dos-like environment before Windows loads. This uses hardly any memory and so nearly all of it is available for testing.


Memory test tools


The CD costs $9.99, but you can download a .iso image and burn it to a CD yourself for free. Boot up with the CD and press C to enter the test configuration menu.


This is provided as a .iso image that you have to burn to a CD. Once this is done, restart the PC and boot up from the disc. You should see a menu from which you can select various tests.

Windows Memory Diagnostic

This free memory tester is provided by Microsoft and when the program is run you are given the option to create a startup floppy disk (does anyone still use these?) or save a .iso image. Save the CD image, burn it to a disc and then boot the PC from it.

DocMemory Memory Diagnostic

You have to register with the website (it's free) in order to get the software. Sadly, this is an old program that is designed to run from a floppy disk. new PCs don't have floppies though, so you might not be able to use it.


This is based on Memtest86 and is therefore similar. There's not much to choose between them and both are good at testing memory.

Windows Memory Diagnostics Tool

This is provided with Windows 7 and so no extra software is required in order to test the memory. Click Start and select Maintenance on the menu, then Windows Memory Diagnostics Tool to start the utility. You are asked if you want to run it the next time you start up Windows. Select the option to do this and then restart Windows. Before Windows loads WMDT runs and thoroughly checks the computer's memory chips. When the two-stage test has been completed Windows will start normally. When the desktop appears a pop-up balloon message just above the Action Center icon reports the result of the memory test.

Useful info...

Memory diagnostic programs come with their own operating system and are often supplied as a .iso image that you can burn to a CD. Windows won't burn .iso images, but there are lots of free CD burners that will do the job. For example, DeepBurner (the free portable edition doesn't need installing - just unzip it and run it). After burning the CD you will need to restart Windows with the disc in the drive. The PC should then boot up from it and the memory test tool will run.

If your PC won't boot from a CD you will need to go into the BIOS setup utility and change the boot options. A few seconds after switching on the PC and before Windows starts to load, press the F1 or Del key a couple of times and you should see the BIOS setup utility appear. Go through each page of options and look for the boot order setting. Change it to CD-Rom first and hard disk drive second, which means boot from a CD if there's a bootable disc in the drive, otherwise start normally from the hard disk drive.