Cisco 7800 Series Media Convergence Servers

Field Notice: MCS-7815 May Experience Blue Screen with Certain Memory Configurations

January 22, 2003

Products Affected


Part Number



Problem Description

Users may experience unexpected Blue Screen errors in Microsoft Windows, followed by a server reboot. Errors indicating a server reboot are seen in the Event Viewer.


The issue is related to the timing of the Celeron processor, operating at 100MHz FSB, and the chipset, operating at 133MHz. Any configuration which differs from those described in this field notice can experience failures.

Problem Symptoms

Symptoms include an unexpected Blue Screen followed by a server restart. A history of these unexpected restarts can be found in the Event Viewer, and will include the error message: The computer has rebooted from a bugcheck.


Memory should be populated on the MCS-7815-1000 as follows:

Memory population should always start in slot 3 and work towards slot 1. DIMM Slot 1 is the slot closest to the processor on the motherboard. Refer to the diagram printed on the inside of the side panel for more detailed information regarding the identification of DIMM sockets.

For DIMMs of the same size: one DIMM - slot 3, two DIMMs - slots 3 and 2, three DIMMs - slots 3, 2, and 1.

For DIMMs of different sizes:

The largest RAM DIMM should be placed in slot 3, the next largest in slot 2, and the smallest in slot 1.

For example: When installing a 512MB DIMM with a 256MB DIMM, the 512MB DIMM would be placed in slot 3, and the 256MB DIMM would be placed in slot 2.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods: