I am utterly confused. Just a month ago I went to a site where the site's SQL Server Database was eating up all the server memory. This is fine, and it was intended. This site was using SQL Server 2008 R2.
Then I went to another two sites which was using SQL Server 2008 R1 and SQL Server 2005, but there were still a lot of memory available.
They were both running the same application with almost similar Query load. In all three servers, the SQL Server's Maximum Memory option was set to max (2147483647) but the memory usage is clearly different.
Any hint on what's going on here?