I noticed unRAID and BIOS were only recognizing 4gb of my 8GB (2× 4GB) of memory. Checked both sticks and they were fine. Then I checked the DIMM slots and one was not working.  I remembered seeing 8GB in the BIOS early so I tried various things to troubleshoot.

 

Sure enough,  when I remove my Dell H310 (flashed to LSI) all DIMM slot works perfectly.

 

I've been poking around in the BIOS for hours, but I'm not finding anything helpful.  I also tried posting this on a more traditional tech support forum but it hasn't gotten any responses.

 

My motherboard is a SUPERMICRO X11SSM-F and it's got the latest BIOS.

 

2× 4GB DDR4 2133Mhz Unbuffered ECC RAM.

 

Intel G4400.

 

unRAID 6.19

 

Any advice,  or even wild guesses would be appreciated.

Wild guess, something to do with the card's BIOS? Maybe the memory that the card wants is mapped to some of the system RAM space?

On the H310 you need to cover pads b5 and b6 with some tape. I have two of these cards and they both caused that problem until I did the tape trick.

 

More information here.

 

http://lime-technology.com/forum/index.php?topic=29236.msg262090#msg262090

 

http://www.vladan.fr/memory-channel-per-bank-getting-non-active-when-using-perc-h310-contoler-card/

 

http://yannickdekoeijer.blogspot.co.uk/2012/04/modding-dell-perc-6-sas-raidcontroller.html

 

Kevin

HA!  I knew I should have asked here first.  I was pretty sure I wasn't the only person encountering this problem but my google-fu failed me on this one.  Thank you digitalfixer, you've lived up to your name!

 

And thanks for the reply jonathanm.