This question is basically an extension of Hyper-Threading and Dual-Core, What's the Difference?
The Bulldozer-based AMD FX processors are marketed as having four, six, or eight cores, but physically consist of two, three, or four modules, each with two cores. It is my understanding that the cores in each module share some silicon, falling in between the virtual cores provided by Intel Hyper-Threading Technology and two physically separate cores. How does this affect the performance of AMD FX cores when used for multitasking or other parallel workloads? What about workloads that depend heavily on floating-point operations, such as Folding@home as well as many games?