Depends what your doing with the PC, since my main use is gaming I'm comfortable running at 1.375.Thing is it's not constant at 1.3 that's just it's upper limit. It still downclocks to 1v and sleeps cores etc. So just unsure if 1.3 is too much when all cores are at 4.2ghz
If you run a lot of core heavy workloads then you would want a lower voltage.