We have TWO of: your standard 2-node active/passive Windows Server 2008 R2 with SQL Server 2008 SP1 Cluster with 1 TB of RAM on the active node and 512 GB on the passive (same on both clusters).

Both OS and SQL "see" the 1 TB of memory and additionally set the following: "min memory" setting to 450 000 (MB) and "max memory" setting to 950 000 (MB)

The problem: every possible monitoring (perfmon metric; red gate sql monitor, task manager, resource monitor etc....) and every possible DMV query show that BOTH clusters cap at exactly 432.6 memory used (PerfMon reports the following for "SQLServer:Memory Manager - Total Server Memory " = 432.6 GB)

I understand the concept behind "it will only use as much as it needs", but I'm certain it can stuff more in there, because the clusters each host 2000+ databases for a total of more than 2 TB worth of often accessed data.

PLUS why would BOTH cluster need exactly 432.6 GB?