I think this helps underscore my point.  Sometimes you get performance, sometimes you don't.<p>I used to work for a major OEM that sold Intel systems. One of the biggest problems was that SQL Server, for instance, ran slower with HT when you had more than 4 threads.<p>But customers never thought to turn it off because they assumed it was a "performance feature."  If it was pitched as a "sometimes" performance feature, then people might be inclined to turn it off to check performance.<p>If I had a dollar for every customer I had to have that discussion with, I could have bought myself a server.