For 1 entire run of x264, it's about an hour, like you can't do anything, only start and stop.
I agree with you on the last part. So doing two-three complete x264s is what I'll do tonight.
Hopefully skylake, or X89 will be easier to OC and won't have the haswell problems.
Side question: is Haswell E and Broadwell E X89?
More like x99.