Memtest Manual

[Courtland Boland]

MemTestverifies the reliability of RAM. A correctly functioning computer shouldbe able to store data in memory with 100% accuracy for months. A computer thatfails these tests,perhaps because of old hardware, damaged hardware, or poorly configuredhardware, will be less stable and crash more often. Even worse, it will become even lessstable over time as corrupted data is written to hard disk.

By using MemTest you can ensure that your computer's RAM is functioning correctly. This is a good thing to check whenever you buy a new computer, install newRAM, or change the configuration of your machine (for instance, to overclockit). If you are the sort of user who likes to push the performance of yourmachine to the edge, relying upon whether your machine will boot after your newBIOS tweaks is a poor way to determine the safety of your new settings. Use MemTest as a true test of stability.

How much RAM to test: Only test theamount of RAM that is unused, rather than the total amount of RAM in your system -otherwise your computer will spend 99% of the test reading and writing to yourhard drive, rather than testing RAM. By default MemTest will check all RAM thatis not in use by other applications. If you want more control, you can use the Windows Task Manager to determinehow much RAM is free. As a rule of thumb, Win9X uses about 32MB of RAM when nothing isopen, and Windows2000/XP uses about 64MB. Vista/7/8/10 use quite a bit more, dependingon what features you have enabled. Even though you cannot directlycheck used 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 fundamentallimitation of using a modern OS. If you need to check every byte, considerpurchasing MemTest Deluxe, which boots off of CD for unfettered accessto RAM.

How long to test: Executive summary: 100% coverage represents a very thorough testing your memory, and will catch all but the most intermittent problems. To catch those much more rare intermittent errors run to 400%.

Empirically we have found that the vast majority of errors are found in just a few minutes. 60% of bad RAM is detected after just 10% MemTest coverage. Running the test 10 times longer (100% coverage) raises the bad RAM detection rate to 95%. The remaining 5% are intermittent errors. Unfortunately, there's no way to speed up detection of intermittent errors - you have to wait for them to happen. The same pattern may be stored accurately the first 1000 times it is written, only to fail on the 1001th write. We have found that testing to 400% coverage will catch almost all intermittent errors, but rather than trying to hit that number exactly, we recommend testing overnight. Your computer is not doing anything else at night anyway. Or, you can run MemTest Pro while you use your computer for other tasks, which can also help identifymemory errors which only show up while the computer is under normal load.

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. Once you start testing MemTest will continue to test your RAM until you tell it to stop, or quit.

How many instances of MemTest: If you have a multi-core ormultiprocessor machine you can make the memory test more effective by runningmultiple copies of MemTest at the same time. Start at least as many copies ofMemTest as you have cores and then divide the amount of RAM to test betweenthem equally.

How MemTest works: MemTest tests the ability of your RAM to store many different unique bit patterns, andto correctly hold those values over various periods of time. More traditional memory checking programs can onlycatch problems which show up immediately. MemTest catches both immediate errorsand long term errors. The longer you run the program, the better the test againstlong term errors. If you can run MemTest overnight without errors then youcan be sure that your RAM functions correctly.

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 your RAM or at the veryleast verifying that your machine is correctly configured. Note that even ONEerror is a sign of a serious problem - a correctly functioning computer can runMemTest for weeks with no errors.

If you do get an error, the next question is to determine how to fix it. The most common cause of memory errors is a faulty memory board. Unfortunately, due to variations inmotherboards and chipsets, it is impossible to reliably locate the physical chip that isfailing purely via software. It is still possible, however, to determine which DIMM is failing by elimination: Run the machine with just one memory board installedat a time; when errors are found the installed board is at fault. This isalso a good diagnostic for another reason: sometimes the problem is really withthe motherboard, and it will disappear if you have less RAM installed, or if the DIMMs are installed in different slots. If you have access to multiplecomputers, you should also try testing the "faulty" RAM in both toisolate whether the problem is the memory or some other component.

If you have more than one DIMM and you find errors with both, evenwhen you test them one at a time, this suggests that your RAM is probably OK.Either your motherboard is failing, you are using memory timing settings thatare too aggressive, or your RAM is not compatible with your motherboard. You canexperiment with memory timing settings in your BIOS, which may allow you to useyour RAM without errors at a small performance cost. Also check that you are using the proper voltage setting for your RAM (not all BIOSes letyou set this). Please refer to yourmotherboard manual for information on this topic - HCI Design cannot providespecific recommendations for BIOS settings.

Another potential cause of memory problems is overheating - make sure yourmachine is well ventilated and try running the test again. If you've triedeverything else, another possibility to consider is that misbehaving drivers canoccasionally corrupt RAM (note that this is very unusual). Try booting Windowsin safe mode, loading as few drivers as possible, and run the check again. Or,consider purchasing the Deluxe version of MemTest, which boots off of its ownCD, eliminating any possible software cause of your faulty memory.

The Deluxe CD package ($14) includes the Windows native Pro version. It addsa 32-bit and 64-bit version of MemTest that runs directly from a bootable CD. Thisversion can be runon any PC and does not require any sort of installation. Useit to check the RAM quality of any PC, whether it has Linux, Windows, or no OSat all. Plus, since it does not load an OS, it can directly access andtest all of your RAM. This is a great disk for computer technicians to carryaround. It also uses the rate that memory is checked as a basic speed benchmark. This can be useful if you aretrying different BIOSsettings. Not only will MemTest tell you if your RAM is still stable, but it willalso indicate if the tweaks you have made improve RAM performance.

I couldn't find the answer to this by searching.. Hoping someone can tell me how to manually enter the memory test screen on a 130xe. I have 3 with bad ram so they automatically go to the test but I just acquired a good one that boots to a blue screen with a "ready" prompt. I'm guessing it's good because it doesn't go to the memory test screen? I'd like to see a fully successful memory test on one of these machines. How can I enter the memory test mode? Is there a special key sequence?

The standard memory test does only 64KB even on a 130XE with 128KB of memory. There is said to be an adapted mem test in late XE's showing full 128KB being tested but I've never seen it. And I never read about it being officially released by ATARI.

Just to avoid confusion: The ROM in the XEGS (rev. 4) is slightly different form the one in the late 65XE/130XE computers. But both process the Reset key identically, so your problem is definitely not caused by the OS.

It could be the keyboard or keyboard connector.. But Ive seen that several times on 130xes caused by a cold solder joint.. Most likely where a resistor goes to the ground plane.. Look for resistors that dont look like any solder came through to the top side of the board when they were soldered. These poor joints tested good at the factory 25 years ago, but over time, oxidization increases their resistance.. They need to be resoldered.

Welcome to another OCC guide! This time I will be covering how to test your computer memory using PassMark MemTest86 software. MemTest86 has a been a staple of the computer industry for testing and resolving computer memory issues since its creation at the turn of the twenty-first century. It has been drastically transformed from its inception in 2002 to what it is today. Around mid-2014, PassMark bought MemTest and breathed new life into the software thanks to a GUI update and UEFI support.

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