Interestingly enough, Microsoft's BASIC was the fastest of all the early home computer BASICs sold in the US. Much faster than Timex Sinclair, Atari, and TI/99 BASIC. And it achieved those speeds with decent precision in FP.

Apple, Commodore, and the IBM PC all used Microsoft BASIC and were the fastest standard BASICs.

Across the pond the BBC Micro had a faster BASIC, and by the mid-80s there were lots of faster BASICs you could buy from 3rd parties.