I notice you didn't list the games which will be rendered unplayable by having it not boost 4 cores to 4.2GHz? Or did you?
I don't think there's a need to have a 2nd system, but I'm also not sure that losing the 0.6GHz boost on 4 cores (so 8 thread?) of a 24 thread CPU is the end of the world either.
That said, I'm also not sure a 0.1GHz boost on 12 cores (24 so threads) is worthwhile either. If you could get all the cores to 3.9/4GHz then I think it's be more worthwhile.
I'm now waiting for AMD to label this chip as the new "Overclockers Dream"!