Fantastic to have this excellent tool back.

However, there is one minor glitch here: /usr/local/sbin/memtest gets installed as owner 502, group 502, giving the second admin user on the machine ownership and write access to the file. This is essentially the same "security issue" as the original 12.0 release of Microsoft Office 2008.

Recommend users run this on their machines: sudo chown root:wheel /usr/local/sbin/memtest

Regardless, I still recommend AppleJack. I don't know about making machines "faster", but it certainly helps to resurrect misbehaving machines, as long as they're not too FUBARed.