@cliffrowley Taking a wild stab in the dark here then but I would guess that this real problem here is Mavericks SSSE3 support for Haswell chips specifically. Maybe we need 

    args << '-no-ssse3' if MacOS.version <= :snow_leopard  || (is_haswell && macOS.version >= :Mavericks)

I'm guessing that if the bug was also present on Snow Leopard for SSSE3 with Haswell we would have heard about it before now from 2013 MBA/iMac owners but can't be sure unless there are any Haswell Snow Leopard users out there willing to test!

I've no idea how to check if a machine is of a particular chip family through homebrew though.. any ideas?


Great work on this btw Cliff, been following it with interest the last 48 hours :+1: