As announced at VMWorld 2012 in San Francisco vSphere 5.1 is now available. Also available are the products vCloud Director 5.1 and vCenter Site Recovery Manager 5.1.
Download VMWare vSphere 5.1
Documentation for VMWare vSphere 5.1
As also announced at VMWorld the one year old vRAM licensing model is now finally history – VMWare returned to the per-socket-licensing model.
By the way – this licensing model applies to vSphere 5.1 and vSphere 5.0, too! (as you can read at VMWare vSphere 5 Licensing, Pricing and Packaging document page 8)