Modules Work in a PC, but Fail on the RAMCHECK

INN-8668-APN16
--Created 5-10-2005

This application note discusses the reasons why RAMCHECK may fail modules that are functional on system boards.

RAMCHECK performs several stringent tests on memory modules. Tests performed include voltage variation tests, which may cause a failure in the module, but may not otherwise occur immediately in a PC. Other tests include data bit pattern tests and our March Up/Down tests, which will catch errors with data patterns that may not be generated immediately by the PC. Due to the astronomical number of data patterns that can be written to a module, data pattern errors are some of the most complex and difficult errors to detect, by any test device. Fortunately, it is common for these errors to occur between adjacent cells, therefore our test algorithms will be able to detect most of these intercell disturbances.

Another factor is the Full Page Burst feature which the RAMCHECK employs on SDRAM devices only. It is not use on FPM/EDO and DDR devices. The RAMCHECK takes advantage of this feature found in some SDRAM devices and uses it to test the modules at a faster rate, shortening the overall test time. The Page Burst LED will flash vigorously throughout the test if the SDRAM device employs this feature. Please note that a FULL PAGE BURST is not a requirement for PC100 or PC133 compliance. Also, those devices having such a feature will not have an advantage in systems over those not employing this feature. Unfortunately the RAMCHECK cannot always determine if encountered errors are due to a real memory array problem or a Page Burst artifact. This is why we recommend that users disable Page Burst in cases of unexplained speed drift or failure. Please visit the following link for more details on this feature and how to disable it, http://www.innoventions.com/ramcheck/rc_ap7.htm

As new memory trends occur in the market, it is often easy to see newer and different memory types being used in each PC. These memory devices are not always supported immediately in our RAMCHECK firmware; therefore, it will usually be necessary for us to make program updates. Information on what each of our program updates contain can be found in our firmware development log on our web site. Program upgrades are recommended once every few months. If the module in question still reports problems after an update, it is possible that the module is not supported by the firmware yet. In this case, we recommend contacting us and providing the specific symptom that was reported by the tester along with module specification (if available) and a sample of the memory device.

We will gladly try to verify and correct problems occurring 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.

CONTACTING OUR TECH SUPPORT DEPT.

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.