Hi,
I have on my infra 4 different generation of AMD Opteron.
I noticed that VMs with CPU/MMU Virtualization set to automatic; the TPS is barely sharing pages, especially for Windows OS.
This happens on the 3 latest opteron models I have in the infrastructure:
On 2356 TPS -> OK
On 3431 TPS -> not ok
On 6172 TPS -> not ok
On 6272 TPS -> not ok
no TPS: 
I checked on the BIOS and every hardware assisted technology for virtualization is enabled.
If you change the CPU/MMU Virtualization to “Intel VT-x/AMD-V for instruction set virtualization and software for MMU virtualization”, do a vMotion and boom, the page sharing goes up.
CPU/MMU Virtualization:
resource allocation:
Of course, using software MMU might be taken into consideration. Check the vSphere Resource Management guide (chapter 5) and the NUMA consideration.
Anyone has already met this behaviour?
thank you in advance
Eric