How BIOS POST Memory Testing Works

The BIOS POST memory testing is performed as follows:

1. The first megabyte of DRAM is tested by the BIOS before the BIOS code is copied from ROM to DRAM.

2. After exiting DRAM, the BIOS performs a simple memory test (where a write/read of every location with the pattern 55aa55aa is performed).

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   Note - The simple memory test is performed only if Quick Boot is not enabled from the Boot Settings Configuration screen. Enabling Quick Boot causes the BIOS to skip the memory test.

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3. The BIOS polls the memory controllers for both correctable and non-correctable memory errors and logs those errors into the SP.

4. The following message appears at the end of POST:

   BMC Responding

5. See How to Interpret DIMM Error Messages in the SEL for information about identifying the BIOS DIMM messages in the SEL.