Hyper-V, Hyperthreading, and per-core licensing

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http://serverfault.com – I've seen lots of people saying we should turn hyperthreading on on hyper-v hosts, but I've got a dilemma. We're going to be running SQL Server 2012 Enterprise on a 2012 hyper-V cluster. This is licenced per core, and in a virtual hyperthreaded environment I think that core is a thread, not a full core. It's also quite pricey compared to the hardware cost :-) If our SQL Server instances start being CPU-bound, how much extra processing power would we get from 4 non-hyperthread cores vs 4 threads (ie equiv to 2 cores)? Should I be considering running my hyper-v environment with hyperthreading (HowTos)