7/29/2019 Diagnosing Bad Memory

http://slidepdf.com/reader/full/diagnosing-bad-memory 1/5

Beginners Guides: Diagnosing Bad Memory

Does your Windows-based PC crash for no apparent reason? Well OK, mine doestoo, but does yours crash often? At random times? With Nasty blue Screens of Death? If the answer is "yes", you may very well have a memory problem. Faulty memory, or

RAM, is often the cause of the dreaded 'flaky PC' syndrome, those hard-to-replicateerrors that get you nasty looks from the store technician because "…nothing seems to bewrong with it. Sir."

In this short but sweet guide, PCstats will discuss the common symptoms of 

faulty memory as well as looking at a handful of free memory testing software programswhich can help you diagnose your troubles.

When good RAM goes bad 

Seeing as it consists only of a handful of Silicon memory chips (called DRAM)soldered to a small circuit board, computer memory is actually much more resistant to

failure than most other computer parts. Having said that, it is also produced anddistributed in more volumethan any other computerpart so it sort of evens out.

Memory DRAM chips aretested by theirmanufacturers before theyare shipped, and this weedsout virtually all the 'defect'

chips prior to sale. However, computer memory is also vulnerable to a variety of situations that can turn your working sticks of DDR or SDRAM memory sour.

Electrostatic shock from improper handling can damage memory. Try to avoidstroking your cat while you install your new 1GB DDR module! Likewise, power surges or

poor power supplies can also damage your computer's memory, sometimes gradually.The same can be said for raising memory voltage too high if you are overclocking.

If your computer is excessively dusty, or is located in a humid environment thecontacts between the memory module and the memory slot can be interfered with orcorroded. Heat, either from other components or the RAM itself can also cause gradual

damage. Obviously, careless handling can also damage computer memory by causingphysical harm to the circuit board or contacts. This is one of the reasons why weadvocate memory heat spreaders - they don't really do much in the way of cooling sticks

of DDR, but they do offer a nice level of protection from handling.

Another factor to take into consideration is the possibility of defects in thememory slots of your computer's motherboard. These can be damaged by the samemeans as listed above, and can cause confusion, since any memory module plugged intoa defective slot will appear to be defective even though it really isn't

Fortunately, as modern computer memory is produced uniformly and hasrelatively few points of failure as compared to other computer parts, manufacturers areable to provide decent warranty support. Most 'brand name' memory purchased directlyform suppliers like Corsair, Crucial or Kingston carries a lifetime warranty, while 'whitebox' memory purchased from resellers typically has a longer warranty than most

equivalent products, generally three years.

7/29/2019 Diagnosing Bad Memory

http://slidepdf.com/reader/full/diagnosing-bad-memory 2/5

Signs of bad memory: 1. Starts Smoking, 2. Becomes Moody...

The indicators of faulty memory are legion, but let's start with a few common ones. Fromthe top:

1.  Blue screens during the install procedure of Windows 2000 or XP. This is one of the surest signs of faulty memory.

2.  Random crashes or blue screens during the running of 2000 or XP. Note that heatcan also be a culprit in the case of general flakiness like this, so you should testfor that possibility too.

3.  Crashes during memory intensive operations. 3D games, benchmarks, compiling,Photoshop, etc.

4.  Distorted graphics on screen. This can also be related to the video card.5.  Failure to boot. This can be accompanied by repeated long beeps, which is the

accepted BIOS beep code for a memory problem. In this circumstance, youcannot test the memory with diagnostic software, so your only option is testingby replacement, either at home or at your computer dealer.

Memory Testing Tips 

Before you run any of the testing

programs below, you should firstdetermine how many memory modulesare installed in your system. If youalready know this, skip to the nextsection. Otherwise, open up yourcomputer. Note that name brandcomputer makers like Dell are rather

touchy about having their systems

opened by the user while still inwarranty.

Keep this in mind, as it's lousy tofind out your memory is bad and your warranty is voided at the same time. Once youhave the side panel off, take a look inside. Memory modules on recent systems look likethis when installed. Note both the number of installed memory modules and the amountof free slots you have.

Once this is done, run one or more of the memory testing applications listedbelow, then proceed to the troubleshooting section. Incidently, that pair of Corsair

memory works just fine, and this picture is just an example of what DDR memory and

DIMM slots look like. :-)

Bad MemoryTesting:Memtest86+ 

Like the Windows MemoryDiagnostic below, thisprogram is available both asa bootable floppy and a CD.This version of the Memtest

software also identifiescertain characteristics of the

system it is running on, likethe chipset, CPU type andmemory speed.

7/29/2019 Diagnosing Bad Memory

http://slidepdf.com/reader/full/diagnosing-bad-memory 3/5

Memtest86+ has basic and advanced testing modes, differing in the time they take andthe thoroughness of the testing. The basic mode should be sufficient to indicate anymajor problems with your memory.

To use Memtest86+ first download either the pre-compiled floppy disk image or thebootable ISO CD image.

Unzip the downloaded file and create your bootable disk by either running the 'install'program (for the floppy disk image) or creating a CD from the ISO image by using aprogram like Nero or Easy CD Creator.

Reboot your computer with the floppy or CD in the drive to start the Memtest86+program. It will automatically begin the basic test. Note the system informationdisplayed to the left of the screen.

The 'c' key will open a menu that allows you to choose between the various test modes.Any errors in your memory will be listed at the bottom of the screen.

Docmem and Windows Mem Test 

Bad Memory Testing: Docmem Simmtester's Docmem program has been around for a while and is in use at many

computer stores and repair shops. It is available free of charge from their website,though it requires a user registration before it can be downloaded.

6. The Docmem program must be installed onto a floppy disk which is then used to boot

the system. It offers both a quick memory test and a 'burn in' mode which loopscontinuously until stopped.

To use Docmem first download and extract the program to a directory, then run the'install' file which will load the Docmem program onto a floppy disk. Restart your systemwith the newly created disk in the drive to start Docmem. Choose the 'quick test' option

to run the memory diagnostic on your RAM. Any failures in your memory will beindicated at the bottom of the screen.

7/29/2019 Diagnosing Bad Memory

http://slidepdf.com/reader/full/diagnosing-bad-memory 4/5

Bad Memory Testing: Windows memory diagnostic 

Microsoft actually offers its own free diagnostic tool in the style of the above twoprograms. The program comes as a Windows installer file which contains a CD image filefor making a bootable CD, and a program to create a bootable floppy.

7. The program is a little more basic than the other two, but still runs through the essentialtests, and has an extended test available for burning in your PC. The program cansometimes identify which memory module is the source of problems on a system whichhas more than one module installed.

To use the Windows Memory Diagnostic first run the executable file and choose either aCD or floppy disk install. If you chose CD, you will be prompted for a location to save aCD image file. Remember the location and use the file to create a CD with Nero or otherCD burning programs.

8. If you choose floppy, simply insert a disk and follow the prompts to create a bootabledisk.

Now restart your system with the CD or floppy inserted. The Memory Diagnostic will start

up and begin running the basic tests. The program will loop forever unless interruptedwith 'x'. Any errors in your memory will be listed at the bottom of the screen.

7/29/2019 Diagnosing Bad Memory

http://slidepdf.com/reader/full/diagnosing-bad-memory 5/5

Bad Memory Troubleshooting 

Once you have determined that your system produces errors when tested with thediagnostic programs above, the next step is to pinpoint the problem areas. If you do

discover errors in your memory, most likely you will need to seek warranty support or

replacement, so make sure you know which module is faulty.

Isolating memory faults

If you only have a single stick of memory, the first thing to do is to run one or more of the utilities below to attempt to detect if the memory is faulty. If you do get errors, yournext step should be to move the lone memory module to another memory slot in yourmotherboard, since there is a possibility of the slot, or at least the contacts between theRAM and the slot being problematic.

To do this first power off the computer. Pull back the two memory retention levers andremove your memory module. Insert the module into another memory slot and push it

down firmly. The memory retention levers should snap into place. If they do not, youprobably have the memory the wrong way round.

Once both levers are locked into place, power on your system and re-run the memorytest(s). If you still get errors, you likely have a faulty memory module.

Troubleshooting with multiple memory modules 

If you have more than one stick of memory in your system and you are experiencingerrors, the next step is to determine where the problem lies. Any one of your memorymodules could be faulty (though if you have recently upgraded your memory and started

experiencing errors, common sense points towards the obvious culprit), as could one or

more of the memory slots on your motherboard.

First step is to remove all but a single memory module (following the direction above)and retest. Test each memory module by itself in the same memory slot. If you get anerror with only one of the modules, you have found your culprit. If you get an error withall of them, the problem likely lies with either the memory slot or the motherboard itself (possibly even the processor).

If you experienced no errors while testing each memory module by itself, but you did geterrors when testing them all together the first time, there is the possibility than one of 

your other memory slots is defective. Try repeating the testing with single memorymodules in the other memory slots on your board, until you find a combination that

gives an error.

Professional Grade memory testing of DIMMs 

There are companies which produce actual memory testing units, once such examplebeing the Innoventions Ramcheck Memory Tester which PCStats reviewed a while back.This is a professional grade memory tester, and it costs a few thousand dollars for thebase unit, and memory-specific adaptor from Innoventions. This is out of the range of the consumer who is looking to diagnose bad memory in their machine, but offers storesor service centers a quick and very reliable way to track down bad memory to the DRAMor even solder point level.