vmware 支援的應該是 two-way virtual Symmetric Multiprocessing (SMP) -- 雙路對稱式多處理器,
也就是傳統的雙CPU(多CPU)架構.
OS 會認為PC裝了兩個同速度的單核心CPU,
所以平均的分配工作給兩個CPU.

根據 VMWARE WORKSTATION 6 的HELP 猜測:

This enables you to assign two virtual processors to a virtual machine on any host machine that has at least two logical processors, or is a uniprocessor machine with hyperthreading enabled.

Caution On hyperthreaded uniprocessor hosts, performance of virtual machines with virtual SMP might be subpar

If the host is a uniprocessor machine (and is not hyperthreaded), assigning two processors is neither supported nor recommended: a warning message will appear.

表示如果你在多核心CPU系統中設定了Vitual SMP 的話,
應該vmware 是真的把指令分配給不同的core (或是 hyperthreading 弄出來的假cpu)去執行.
(有錯請指正)

在 vmware 5.5 以前,使用 AMD K8 CPU 的話,
HOST OS 真的必須裝完所有DRIVER,
Guest OS 還要做一些設定才不會當機.
現在vmware 6.0 以後的版本就沒有這樣的問題.