I have recently pushed the main ESX host for TNS to 70% overcommit on RAM, since upgrading to 4.1. Interestingly (expectedly), the performance now is the same as it was on 3.5 with 2 fewer VMs and only 50% overcommit. But, it’s still pretty poor in the “Lab” performance pool, even after changing that pool from “low” to “normal” shares. So we finally ordered new memory, doubling the server to 16gb. It goes in Sunday night, so we’ll see how things perform next week when Rob’s on site with customers.