Each license for vSphere 5.0 bestows a vRAM capacity entitlement. That entitlement corresponds to a quantity of vRAM that can be assigned to virtual machines (VMs). vRAM entitlements are pooled across all the hosts and VMs attached to a vCenter Server. The amount of vRAM in the pool can be distributed across any of the hosts within the pool. VMware places no restrictions on the number of VMs that can run in the pool, as long as the summation of their vRAM (for those powered on) doesn't exceed the amount in the pool. Compliance is measured along a 365-day moving average of the daily high watermark for vRAM assigned to powered-on VMs.