Tom's Hardware Guide compares Intel's with AMD's server processors:
Our primary goals in this article are to shed some light on the performance differences between the current AMD and Intel platforms in a heavily multithreaded server environment, and to see how well the platforms scale. Since the systems we used were on loan from a local dealer we had limited time for testing, and could not test every type of applications. One application we did look at is ESX Server; this is an important topic these days, as VMware's operating system can bring any server to its knees if you run many logical servers on it as virtual machines.
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