rbowman1234
1 Copper

Precision 690 w/memory risers booting in single channel mode

Good afternoon. I searched the general desktop forum for an answer to this but didn't find anything.

I have a Precision 690 with a set of memory risers. I have verified that they are properly configured with 4 sets of matching fully buffered 4GB DIMMs, but when I boot, I get an error message that it is booting in single channel debug mode. When I hit F2 and look at the memory menu, it shows that all 16 4GB DIMMs are present, but only 8GB is available.

I bought this refurbished from my university with mismatched DIMMs on what turned out to be risers that weren't fully functional. I replaced the risers and memory. Is there an additional step I am missing to take the machine out of debug mode?

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3 Replies
bmcowboy
3 Zinc

Re: Precision 690 w/memory risers booting in single channel

Hi @rbowman1234 ,

Check out this thread with solution and see if same story as yours.

“May the Force be with Dell.”
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rbowman1234
1 Copper

Re: Precision 690 w/memory risers booting in single channel

Thank you for the reply. That doesn't help. I have all 16 slots filled, and when I view the memory after striking F2 in debug mode, it shows every slot filled but still only boots in single channel debug mode.

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bmcowboy
3 Zinc

Re: Precision 690 w/memory risers booting in single channel

Hi @rbowman1234 ,

Checked on the user's guide starting from page #121. Make sure the followings:

  1. All memories must be matched in size, rank, and organization (ideally to be identical memories, same brand and model). If any of the 3 components not matched, system will not identify it as useful, as well as it's partner in pairs.2.jpg
  2. Only the DIMM_1-4 slots (the slots with the white securing clips) on the system board can be used with the riser cards. The other slots (DIMM_5-8) must be left vacant.1.JPG
  3. Further checked on the Spec Sheet. It stated that "1KW chassis required for memory expansion greater than 32GB (greater than 8 DIMM slots)." Make sure you memories and PSU match with this requirement.
  4. A discussion here pointed out whether memories in dual-rank or quad-rank may make a difference. Not sure if it's correct but check what kind of yours first.

 

“May the Force be with Dell.”
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