I just heared Transparent Page Sharing (TPS) is disabled by default in latest ESXi 5.5 patch. You may concern about that if your IT budget is tight since it means you need more memory for heavy virtual machines.
听说ESXi 5.5最新的patch里把TPS禁用了，专门研究了一下。觉得这对IT预算紧张的企业可能是个坏消息，因为这意味着你需要更多的内存应付大型虚拟机。
Here is some information about the change.
What is Transparent Page Sharing (TPS) ?
Why is Transparent Page Sharing (TPS) disabled by default?
How to re-enable Transparent Page Sharing (TPS) ?
You could find how Transparent Page Sharing (TPS) works now on your environment by esxtop by press m.
Chinese Version
英文版中有TPS和这次变更的链接，以下为中文意思。
通过esxtop中点击m键，你可以看到当前TPS如何应用于你的系统。（参见英文版中的截图）