As you know the new ESX Server 2.1.0 introduces HyperThreading support, improving virtual environment up to 30% according with Intel official benchmarks.
Before ESX 2.1 release many users asked in newsgroups and web forums informations about how HT impacts on virtual machines performances, and many skilled users on computer architectures or kernel development tried to answer the important question.
Now, some weeks after ESX release, VMware releases an interesting paper about HT. A must read, for all VMware customers.
Go on and read it here!