We've recently upgraded the RAM on a Windows Storage Server 2008 R2 Standard to 32 GB.
When I open the System panel, it indicates Installed memory: 32.0 GB (16.0 GB usable). Why is that?
I've been trying to dig up documentation that would indicate that this is a limit of the operating system version, but I've come up short. Looking at the version comparison on Wikipedia shows no version with 16 GB, but Storage Server isn't listed and Memory Limits for Windows and Windows Server Releases doesn't list Storage Serer 2008 R2.
I've since found an infographic in the blog post titled Windows Storage Server 2008 R2 is now available!, which indicates that the limit would be 32 GB.
As suggested by @Nico, opening perfmon shows that 16 GB of memory are "reserved for hardware".
The installed RAM modules are 4 x 8 GB Hynix HMT31GR7CFR8A-H9 RDIMM.
Support advised us to perform a firmware upgrade of the mainboard. We performed the firmware upgrade, but it had no effect on the issue