I have a windows 2008 r2 server running ADFS2 and some web apps that is having issues with low memory.
Digging around I found that the 5.5 GB were being used under Kernel Memory (paged).
Further digging with Poolmon, I discovered that the majority of that (5GB+) was being used by CM - configuration manager. Also known as the registry.
I'm really now sure how to tell why the registry is using so much memory however, or how to release it? Looking at the physical registry files they don't appear that large.
EDIT #1 Using the powershell script @ http://jdhitsolutions.com/blog/2011/05/get-registry-size-and-age/ confirms what I saw looking at the physical registry files, that they're relatively small
Computername : (removed) Status : OK CurrentSize : 67 MaximumSize : 2048 FreeSize : 1981 PercentFree : 96.728515625 Created : 4/1/2011 11:38:02 AM Age : 454.23:41:28.2540682