Apple Server Diagnostics - Manual (Page 47)

Appendix Server Diagnostics Test Reference 47
Multicore Memory Tests
Multicore memory tests test the first 2.5 GB of memory using all available CPU cores.
In Server Diagnostics EFI, all memory tests (simple, multicore, and extended) are
grouped under Memory tests.
Note: The time required to complete memory tests correlates to the amount of
memory being tested. These estimates are based on testing 1 GB of memory.
Test Estimated completion time Description
MP Block Checkerboard 5 seconds Alternates 32-bit words with all
1s and all 0s, and then with all
0s and all 1s.
MP Bit Checkerboard 5 seconds Alternates bits with all 1s and
all 0s, and then with all 0s and
all 1s.
MP Sequential Byte Block 8 minutes Fills all bytes sequentially with
patterns starting at 0x00 and
ending at 0xFF.
MP Walking One 2 minutes Walks 1s up and down memory.
MP Walking Zero 4 minutes Walks 0s up and down memory.
MP Walking Spread Bit 4 minutes Walks 0b01 up and then walks
0b10 down memory.
MP Walking Bit Flip 4 minutes Alternates words with walking
1 and walking 0, and then
alternates words with walking 0
and walking 1.
Check Hardware Errors 1 second Tests specific registers for
memory related errors. Running
this test at the end of memory
testing may help catch memory
errors generated during other
memory tests.
Extended Memory Tests
Extended memory tests test all available memory.
In Server Diagnostics EFI, all memory tests (simple, multicore, and extended) are
grouped under Memory tests.
The availability of extended memory tests depends on the server model you test.
Note: The time required to complete memory tests correlates to the amount of
memory being tested. These estimates are based on testing 1 GB of memory.