At the recent VMworld 2012 event, VMware announced the elimination of vRAM licensing for vSphere, moving back to the per-socket model (and eliminating core restrictions in the process).
There seems to be some confusion as to whether or not this applies to vSphere 5.0 or if the move was a sinister plan to force all customers to upgrade to the latest release, recently-announced version 5.1.
It’s simple: there is no more vRAM entitlement in any version of vSphere — not in 5.1 and not in 5.0.
In the VMware vSphere 5 Licensing, Pricing, and Packaging document, the FAQ section makes it very clear:
Q: Does the new VMware vSphere 5 licensing model – per-CPU
without limitation on the number of VMs, cores or amount
of physical RAM – apply to both vSphere 5.0 and vSphere 5.1?
A: Yes. The VMware vSphere 5 licensing model applies to both
vSphere 5.0 and 5.1 customers.
VMware vSphere 5.1 is an awesome product, but you are not forced to immediately upgrade in order to enjoy the benefits of this recent change.