@Sh41 @aperezdc @electron_greg The floating point representation and math differs quite a lot between these old machines, including in the precision. MSX uses doubles by default, 14 digits precision. That's quite some overhead for these simple FOR loops used here.
However, dropping to single precision (DEFSNG A-Z) the time goes down from 53.4s to 50.8s.
Might be fun to compare the "integer version" performance of this code on these machines. The MSX version thus is 26.4s.