Question Gigabyte Z690 Aorus Pro fully populating RAM

Jul 21, 2021
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For a while I've been running a Gigabyte Z690 Aorus Pro (the DDR5 version) with a pair of Crucial CT32G48C40U5 32GB DIMMs installed. The mobo has the latest F8f BIOS installed. I recently found the exact same DIMMs on sale at a considerably better price, so I bought a couple more to max out the memory on the motherboard. After installing the two additional sticks, the motherboard wouldn't complete POST - the two character debug codes that it displays would go through a sequence, then start again and repeat the sequence, then start again and repeat the sequence...it never got as far initializing the displays and showing the BIOS message to hit <DEL> to enter the BIOS. The sequence always ended with code 54 showing - the mobo manual lists codes 50-55 as indicating memory initialization errors.

I powered the mobo off and removed one of the new sticks from DIMM slot B1 (the other new stick was in slot A1). The machine then booted OK with the BIOS showing 96GB RAM. I powered it off and swapped the new stick in slot A1 with its sibling, to see if it still booted OK (it did). I then installed the remaining new stick in slot B1, and the motherboard then booted OK with BIOS showing 128GB RAM.

I was a bit mystified by this sequence of events - can anyone offer any suggestions?
 
Mixing RAM outside a kit is never guaranteed to work and needs trial and error to initialize. When you tried different combinations, the combination that clicked actually initialized the logical sequence of throughput hence working as deemed. Its pretty common when mixing RAM, and it seems like that's what happened.
 
For a while I've been running a Gigabyte Z690 Aorus Pro (the DDR5 version) with a pair of Crucial CT32G48C40U5 32GB DIMMs installed. The mobo has the latest F8f BIOS installed. I recently found the exact same DIMMs on sale at a considerably better price, so I bought a couple more to max out the memory on the motherboard. After installing the two additional sticks, the motherboard wouldn't complete POST - the two character debug codes that it displays would go through a sequence, then start again and repeat the sequence, then start again and repeat the sequence...it never got as far initializing the displays and showing the BIOS message to hit <DEL> to enter the BIOS. The sequence always ended with code 54 showing - the mobo manual lists codes 50-55 as indicating memory initialization errors.

I powered the mobo off and removed one of the new sticks from DIMM slot B1 (the other new stick was in slot A1). The machine then booted OK with the BIOS showing 96GB RAM. I powered it off and swapped the new stick in slot A1 with its sibling, to see if it still booted OK (it did). I then installed the remaining new stick in slot B1, and the motherboard then booted OK with BIOS showing 128GB RAM.

I was a bit mystified by this sequence of events - can anyone offer any suggestions?
Might have been no more than a bad connection.

You might want to let memtest86 run for some hours just to see if something is going to pop up.
 

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