Xeon 5600 series brings six-core chips to 2P systems
 

Most of the entrants in the table above are fairly straightforward, though several are notable for their strangeness. Several low-voltage Xeons with two of their cores disabled can fit into 40W power envelopes, which is fairly remarkable. A handful of others are workstation-tailored parts with 130W power envelopes, including the Xeon X3680, which looks to be essentially the same thing as the Core i7-980X, though with Xeon validation and branding behind it.

No doubt most of the attention from IT administrators will focus on the 95W and 80W parts, which are the mainstream offerings. Note that many of the 80W Xeons in the 5600 series are quad-core, eight-thread models with two defunct cores. The six-core parts carry a bit of a price premium.

http://techreport.com/discussions.x/18618