The reason MX Linux performed so well is, because, it uses some core components from Antix Linux Distro, which is optimised. based on Debian's "stable" branch.
MX Linux is a cooperative venture between the antiX and former MEPIS communities, using the best tools and talents from each distro. It is a midweight OS designed to combine an elegant and efficient desktop with simple configuration, high stability, solid performance and medium-sized footprint.