PC Diagnostics, Testing, and Maintenance - Upgrading and Repairing PCs - page 1275

• Identify the type of memory.
• Identify the memory speed.
• Identify whether the memory has parity or is using bogus parity emulation.
• Vary the refresh timing and access speed timing.
• Locate single bit failures.
• Detect power- and noise-related failures.
• Detect solder opens and shorts.
• Isolate timing-related failures.
• Detect data retention errors.
Conventional memory diagnostic software can't do these things because it must rely on
the fixed access parameters set up by the memory controller hardware in the motherboard
chipset. This prevents the software from being capable of altering the timing and methods
used to access the memory. You might have memory that fails in one system and works
(mostly) in another when the chips are actually bad. This type of intermittent problem is
almost impossible to detect with diagnostic software. Two companies making testers in-
clude CST ( www.simmtester.com ) and Tanisys ( www.tanisys.com ).
For smaller companies, repair shops, and individuals that must rely on PC-based memory
testing, I recommend two programs:
• MicrosoftWindowsMemoryDiagnostic — http://oca.microsoft.com/en/windiag.asp ;
also included in Windows Vista and Windows 7
• Memtest86 — www.memtest86.com
BothoftheseprogramsofferacomprehensivesetofmemorytestsinabootableCD-ROM
format andareavailable fordownloading atnocharge.Thismeans that nosoftware needs
to be installed on the PC being tested; you merely boot from the test CD and run the dia-
gnostics.
See Chapter 6 , “ Memory ,” p. 315 for more information on memory in general.
Special Tools for the Enthusiast
All the tools described so far are commonly used by most technicians. However, a few
additional tools do exist that a true PC enthusiast might want to have.
Electric Screwdriver
Perhaps the most useful tool I use is an electric screwdriver. It enables me to disassemble
and reassemble a PC in record time and makes the job not only faster but easier as well.