Question Only 24 GB of 32 GB Available?

[sirstinky]

Hi all. I inherited a 2010 vintage Dell Precision T7500 workstation and it's amazing, but is having some quirks. It's dual Xeon E5530 (one on a riser), has 500 GB SSD, and is currently set up with 32 GB of RAM. All the DIMMs match each other and are non ECC DDR3 1066 (8x 4 GB).

Here's the issue I'm having. In the beginning, I had a message on POST after the RAID controllers loaded saying memory failure riser DIMM 2. I switched the memory around and went to triple channel 24 GB and it says memory failure riser DIMM 1. When I look in Windows system it says 24 GB installed, but only 20 GB available. I switched the modules around and same issue. I switched them again back to 32 GB and it says 32 GB, but only 24 GB available. I ran the Dell diagnostics and everything is fine, no ram errors. I checked the BIOS and it shows the DIMMS installed. I don't know what's going on here. Is something wrong with the way the modules are installed? I know it can be finnick lying since it's a dual cpu on a riser. I cleaned out the suspect slot with compressed air and very lightly with rubbing alcohol on a lint free pad. I switched around known good modules.

The BIOS is updated to A16 version, by the way.

Any help is appreciated
Nick

 

[stonecarver]

http://sivirt.utsa.edu/Documents/Manuals/precision-t7500_Service Manual_en-us.pdf

Maybe in here you can find the answer it shows the memory configurations

It seems looking at Service Manual with duel Processors installed you can not get system to run with 32gb. It is 24gb or jumps to 48gb with x2 installed Xeon CPU's. But with a single Xeon you can do 32gb. I don't get it but ?