We had the same problem with a 12GB server - I'm extremely surprised that this particular hotfix isn't more widely cited, since it seems to cause a lot of problems. We were getting a very subtle message in the SQL log that basically said "Failed to allocated specified memory, using this amount of memory instead". Punching this error message into Google, one would hope, would have turned up this hotfix KB, but instead I stumbled upon it months later in an otherwise poor article about large memory configurations.