hcidesign.com) MemTest 3.1 | (c) 2005 |
MemTest is a RAM reliability tester. It evaluates the ability of your computer's memory to store and retrieve data. A correctly functioning computer should be able to do both these tasks with 100% accuracy day in and day out. A computer that fails these tests, perhaps because of old hardware, damaged hardware, or poorly configured hardware, will be less stable and crash more often. Even worse, it will become even less stable over time as corrupted data is written to your hard disk.
By running MemTest, you can ensure that your computer's RAM is correctly functioning. This is a good thing to check whenever you buy a new computer, install new ram, or change the configuration of your machine (for instance, to overclock it). If you are the sort of user who likes to push the performance of your machine to the edge, relying upon whether your machine will boot after your new BIOS tweaks is a poor way to determine the safety of your new settings. Use MemTest as a true test of stability.
Please read this section before contacting technical support. There are some brief guidelines at the end for typical testing procedures, and comments on typical results.
Unlike other memory checking software, MemTest is designed to find all types of memory errors including intermittent problems. Therefore, it needs to be run for several hours to truly evaluate your RAM. The best way to use the system is to set it up to run overnight, for a fully rigorous test. Letting MemTest run long enough to achieve 100% coverage will only identify RAM that frequently corrupts all data written to it. You can also run MemTest while you use your computer for other tasks, which will help identify memory errors which only show up while the computer is under load.
Note that MemTest will report any errors that it finds as soon as it finds them, so if you do not see any error messages, then all testing so far has been successful. Also note that once you start testing, MemTest will continue to test your RAM until you tell it to stop, or quit. The tests can run as long as you wish, and become more rigorous the longer you let them go.
To keep the test running smoothly and quickly, you should only test the amount of RAM that is free, rather than the total amount of RAM in your system - otherwise your computer will spend 90% of the test reading and writing to your hard drive, rather than testing RAM. You can use the Windows2000/XP Task Manager, or the Windows 9X System Monitor to determine the proper amount of ram to check. As a rule of thumb, Win9X uses about 32MB of RAM when nothing is open, and Windows2000/XP uses about 64MB. Even though you cannot directly check this RAM, Windows dynamically moves the location of most of its subsystems, so most of your RAM will be checked eventually.
No Windows program can directly check the RAM used by the OS; this is a fundamental limitation of using a modern OS. If you need to check every byte, consider purchasing MemTest Deluxe, which boots off its own floppy for unfettered access to RAM.
In general, the longer the test, the better. Here are three typical lengths of testing you might try:
In all cases, if MemTest finds an error it will stop and report it to you. If you do get an error, you should consider replacing you RAM or at the very least verifying that your machine is correctly configured. If you have any questions, please take a look at our FAQ page before contacting tech support.
MemTest tests the ability of your RAM to store many different unique bit patterns, and the ability to correctly hold those values over long periods of time. More traditional memory checking programs can only catch problems which show up immediately. MemTest catches both immediate errors and long term errors. The longer you run the program, the better the test against long term errors. If you can run MemTest overnight without errors this means that your machine can function for that period of time without making a single memory error, even when the RAM load is very heavy. Statistically, it also means that your machine is always able to function without memory error.
If you only want to catch short term errors, then run MemTest until it reports 400% to 800% coverage - this should take less than 10 minutes for most machines, unless you have a lot of RAM. This will catch all but the most subtle memory errors.
If, during testing, MemTest turns up any errors, your RAM is faulty. You should replace it immediately. Unfortunately, due to variations in motherboards and chipsets, it is impossible to reliably locate the physical chip that is failing purely via software. If you have more than one SIMM/DIMM, you can isolate the faulty one by elimination: Run the machine with one memory board installed at a time; when errors are found the installed board is at fault. This is also a good diagnostic for another reason: sometimes the problem is really with the motherboard, and it will disappear if you have less RAM installed.
The normal version of MemTest is a Windows native program, and is free for all users. There are also two other versions available:
The Pro version ($5) is also a Windows native program, and similar to the normal version. It is tuned, however, to the needs of users who diagnose the quality of ram often, or on multiple machines. It offers options like a "nice" mode which allows you to test RAM in the background, during normal use of the machine, as well as more detailed reporting of errors. It also does not pause every time an error is found, so it can be used to determine the overall reliability of ram that is prone to errors, rather than just as a tool that determines if there are any errors at all. Finally, it can be run without the "first time user" messages.
The Deluxe package ($12) includes the Windows native Pro version. It adds an embedded version of MemTest that runs from a bootable diskette. This version can be run on any PC with a floppy drive and does not require any sort of installation. Use it to check the RAM quality of any PC, whether it has Linux, Windows, or no OS at all. Plus, since it does not load an OS, it can directly access and test all of your RAM. This is a great disk for any computer technician to carry around. It also uses the speed that memory is checked as a basic benchmark of computer speed. This can be useful if you are testing different BIOS settings. Not only will MemTest tell you if you RAM is still stable, but it will also indicate if the tweaks you have made improve RAM performance.
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Questions about this product? Visit its online home, at http://hcidesign.com/memtest,
or send your question to technical support (memtest31hcidesign.com)