Quote Originally Posted by LarsMarkelson View Post
Sorry this may have been asked before but does anyone know why hyper-threading lowers GFlops score? This is on my i7 920 system... non HT scores are significantly higher than HT On at the same clock speeds.
Because Intels linpack routine is about the only app out there that fully utilises all capabilities of the CPU. SMT was designed to boost performance for poorly coded/optimised (but multithreaded) applications, but when the CPU faces something as efficient as linpack, Hyperthreading actually backfires. Still causes your CPU to heat up more, so I'd leave it on for testing if you normally run with HT enbabled.