Dell Poweredge R410 Memory Config

Josh Rogalski
Josh Rogalski used Ask the Experts™
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I had this question after viewing Dell server memory configuration on R410.

I have a PowerEdge R410, I recently purchased additional memory for the server.  I have 16Gb originally, 4 sticks of 4GB each.  I purchased 2 16GB sticks hoping I could bump it up to 48Gb total.  What I am finding similar to the article above is that no matter the configuration, it disables specific dim slots.  Is there any configuration I can use that would allow me to have all 48 gigs usable?   It is very frustrating as I thought

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Top Expert 2014

Commented:
how many cpus do you have?
Josh RogalskiNetwork Technician

Author

Commented:
2 CPU's.  Most I can get it to recognize is 32gb at any given time.  That is with 16gb in slots A1 and B1, 4gb in slots A2, A3, B2, B3

Commented:
The manual (p 119) has many many rules. Did you follow them all? Check both the existing and the new modules for speed, rank, RDIMM/UDIMM etc., then check it all against the rules.
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Top Expert 2014

Commented:
Should work. maybe an OS limitation.
Philip ElderTechnical Architect - HA/Compute/Storage

Commented:
The key to the memory setup is the number of ranks per channel.

Each channel can have a maximum of 8 ranks.

The 4GB sticks are probably low density so 4x per DIMM (4 Ranks) thus the ability to use one 16GB and one 4GB stick only. If the 16GB is 2x (2 Ranks) then the limitation would still be there.

If the 16GB and the 4GB sticks were 2x (2 Ranks) then you'd be able to populate the channel with all three.
Josh RogalskiNetwork Technician

Author

Commented:
Philip, does this mean in theory I should be able to install a 16gb stick and 1 4gb stick in the A and B slots respectively? If the ranks are as you mention?
Top Expert 2014

Commented:
***a 16gb stick and 1 4gb stick***

Please post photos of the DIMMs you have and your motherboard. We can't tell if they are compatible without.
Technical Architect - HA/Compute/Storage
Commented:
A1 = 16GB
A2 = 4GB
B1 = 16GB
B2 = 4GB
Josh RogalskiNetwork Technician

Author

Commented:
I believe this is going to work.  I will close this out for now and will post again with confirmation once I can take this server down.  Appreciate everyone's help!
Top Expert 2014

Commented:
You should be able to use all four of the 4GB ones. The R410 only uses two memory channels per CPU and with max 2 DIMMs per channel you can't exceed the maximum rank limit. What are the part numbers for the new DIMMs and what part number for the original? We can look the original ones up for you if you give us the serial number if that's what it came with originally.
Josh RogalskiNetwork Technician

Author

Commented:
Ok, so the suggestion of A1 - 16, A2 - 4, B1 - 16, B2 - 4 didn't work so I am back to the drawing board.  I am showing the memory models I have as I took a picture while the server was powered off. Any suggestions?  I have a total of 2 sticks of the 16gb, and 4 sticks of the 4gb.


memory
Top Expert 2014

Commented:
Should work. Do you see all the RAM in BIOS or diagnostics? If you ro it is probably an OS limitation.
Josh RogalskiNetwork Technician

Author

Commented:
I do see all of it, and the OS does as well, but claims 32gb usable.  I also get an error message in BIOS bootup claiming that one of the DIMMs is going to be disabled.  Server is Windows Server 2012 R2 Standard, which supports a ton of memory higher than that as I recall. I am reading 32gb but DIMM A4 is being "disabled" according to the BIOS.  It claims something about a "lane failure".  Not sure what is going wrong here, unless one of the memory modules is not working.  I guess that could be happening. See attached photos
openmanage.jpg
memerror1.jpg
memerror2.jpg
Top Expert 2014

Commented:
You only have 3 DIMMs per CPU, so slot 4 should be empty. You must have them in the wrong slots. The slots furthest from the CPU have to be populated first as they terminate the buses, BIOS disables them if they are in the wrong slots.

The lane failure may not be a real fault, just noise on that lane due to using the wrong slot.
Josh RogalskiNetwork Technician

Author

Commented:
Can I just take the 16 gig sticks and put them in A3, and B3?  So:

A1 - 4
A2 - 4
A3 - 16
A4 - NOTHING

B1 - 4
B2 - 4
B3 - 16
B4 - NOTHING
Top Expert 2014

Commented:
Anything will work so long as you do not use the slot 4s. I don't know what slots are on what channel so can't tell you how to put 8GB on one and 16GB on the other but 4GB on one and 20GB on the other doesn't perform too bad anyway.

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