One of the PCs you support is acting up—freezing, crashing, blue screening. Is some piece of hardware failing? Is some newly installed application causing trouble? Or could it be faulty memory? One way to find out for sure is with the free Microsoft® Windows® Memory Diagnostic utility. This tool will run a variety of tests on your PC's RAM to determine whether flaws exist in any of the modules.
Figure 1 Windows Memory Diagnostic options for creating bootable media (Click the image for a larger view)
Create Startup Disk, from which you can create a startup floppy disk with the program.
Save CD Image to Disk, from which you can save an ISO image of the program to your hard drive. Then you can burn that image onto a CD and make it bootable using CD creation software. After you build your bootable media, reboot your PC and start the diagnostic from the floppy or CD.
When the program loads, it immediately begins scanning your RAM. The Windows Memory Diagnostic tool starts in Standard mode, which includes 6 different, successive memory tests, each of which uses a unique algorithm to scan for different types of errors. A screen displays each individual test as it runs, listing its progress and the range of memory addresses being scanned. After those 6 tests complete, the tool runs another pass using the same tests and will continue running pass after pass until you exit the software. Typically, though, one pass should be enough to tell whether or not the memory is faulty.
For more exhaustive testing, you can switch to Extended mode, which runs 11 separate memory tests. There's also a Basic mode that runs only 2 tests, but, to be thorough, you'll want to stick with the Standard and Extended modes. If you run the extended test suite, it is suggested that you let Windows Memory Diagnostic run overnight.
After each test completes, the tool displays a Succeeded or Failed message. A Failed message is followed by details about the failure and typically indicates a fault with one of your RAM modules. Depending on your PC environment, the diagnostic may be able to narrow down a memory problem to a specific module.
In this case, an option to View errors by memory module will appear in the menu. This option can help you determine specific modules that are failing and should be replaced.
In the Advanced options screen, you can switch among Basic, Standard, and Extended mode. Here you also can turn off the processor's cache during the scans, which forces the tool to access data directly from RAM, ensuring more thorough testing. The System Information command lists the capacity and type of RAM installed in each slot.
Windows Memory Diagnostic supports x86-based platforms, including Intel Pentium and Celeron processors and AMD K6, Athlon, and Duron CPUs. However, the tool can address only up to 4GB of RAM and will not scan beyond that range.
You will also find a version of this diagnostic installed in Windows Vista® under Administrative Tools and on the Windows Vista installation media under the Repair option. The Windows Vista version does not provide as much visual feedback or as many options, however. So you will want to be sure to keep the standalone edition handy for the next time one of your PCs starts acting up.
Lance Whitney is an IT consultant, trainer, and technical writer. He has spent countless hours tweaking Windows workstations and servers. Originally a journalist, he took a blind leap into the IT world 15 years ago.