Hi,

From the Dell PowerEdge R430 Owner's Manual, there is this guidelines:

• Populate memory module sockets only if a processor is installed. For single-processor systems, sockets A1 to A8 are available. For dual-processor systems, sockets A1 to A8 and sockets B1 to B4 are available.
• Populate all sockets with white release tabs first and then the black release tabs.

Please check the configuration.

Regards