[mriet]

Wonder if he tried zstd --long=31

Or, given that he's basically mentions FCM/PPM, zpaq.

[aghilmort]

+1'd, came here to mention same, if need optimal, zpaq or variants

plus height map data is prolly pretty hard to compress assuming normal distributions, etc

85% of optimum at IO speeds is pretty good using zstd especially default options is pretty good