Tests on Phoronix show Clear having significant wins in a number of tests. They have done so by rewriting libraries to perform well with Intel hardware. Those who complain about a 25% performance hit elsewhere can now be shown pretty good performance with Clear that isn't attainable with other distros.
Oh, gotcha; boost from optimizations cancelling out against loss from patches. I would argue that that still constitutes a performance loss since before the patches you could run with just the improvements get better performance rather than neutral. But you're not wrong.