Accounting for up to 56% of market share in the US and 40% worldwide, the quad-socket market is the last stronghold of AMD. It is a small stronghold, as for every 4S server, there about 17 dual-socket and four single-socket servers sold. However, since each 4S server contains four CPUs, the 4S server market accounts for about 10% of the server CPUs sold. More importantly, the margins are quite a bit higher than in the popular 2S market, and as a result those 10% of server CPU shipments are good for 20% of the revenue, and it gets even better.
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*Source: Anandtech (
http://it.anandtech.com/IT/showdoc.aspx?i=3335)*
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