Modules Fail in a PC, but Pass on the RAMCHECK

INN-8668-APN17
--Created 5-10-2005

Some modules seem to fail on a certain computer while passing a test on the RAMCHECK system (or any other memory tester). This application note discusses the possible reasons.

Modules failing in a PC, but passing RAMCHECK even after a program update, may in fact be good modules after all. Today's computer systems require strict timing parameters that must be observed before installing and using the memory module. If the module has a slower speed than the motherboard is expecting, an error will likely occur, whereas installing the same memory component on a different system will cause no error. Such a module may also work in a slower system.

It's also important to realize that not all modules are drop-in replacements for every system board. Some modules have key differences in wiring that will prevent them from working on certain system boards. Before installing the memory device, you should consult the system manual for any information on the exact module type required (i.e. sizes supported, mode type, etc.)

Another possible problem that would cause such a situation would be a module pattern sensitivity problem. This is one of the most complex problems that could occur in a memory device, making the testing of these components that much more complicated. The number of possible memory patterns for a typical 256M chip is an astronomically large [order of 2^256,000,000]. Running a complete exhaustive pattern test on a such a module would be theoretically impossible, even on multi-million dollar test equipment. For more information on the RAMCHECK test algorithms and accuracy please visit the following link: http://www.innoventions.com/ramcheck/rc_ap5.htm

Our R&D department looks forward to verifying and correcting problems that occur with memory devices. If you should decide to send samples of modules that are not supported in our firmware, or otherwise causing problems that are not detected, please contact our Technical Support department.

CONTACTING OUR TECH SUPPORT DEPARTMENT.

For more information, please call us at (281) 879-6226 M-F 9:00-5:00 CST, or send your E-mail to support@innoventions.com, or fax your message to (281) 879-6415. Please remember to include your phone and e-mail.