REDMOND, Wash. — When he was chief executive of Intel in the 1990s, Andrew S. Grove would often talk about the “software spiral” — the interplay between ever-faster microprocessor chips and software that required ever more computing power. The potential speed of chips is still climbing, but now the software they run is having trouble keeping up. Newer chips with multiple processors require dauntingly complex software that breaks up computing chores into chunks that can be processed at the same time. The challenges have not dented the enthusiasm for the potential of the new parallel chips at Microsoft, where executives...