Excel uses multiple cores for calculations. You can configure how many to prevent it sucking up the entire CPU for long calculations.

It's a pretty easily parallelizable problem since the sheet is just a dependency tree with the cells as nodes.

The build-in functions (e.g. probability distributions etc.) could also be multi-threaded, although I'm not sure if they are. Our external API called from cells was written in C++ and already multi-threaded.

More info here:

https://msdn.microsoft.com/en-us/library/office/bb687899.asp...

It's a NP complete problem. What I mean is, there is no generalisable solution to this. Optimising algorithms employed by sophisticated technical users (think `-O`optimisation; Java hotspot) typically employ sets of heuristics that run the code in more optimal ways based on certain patterns. To trigger these you usually have to be aware of them and write your code in a certain way.

Given that Excel isn't really targeted at these kinds of user (heavy lifting typically offloaded to external libraries) it wouldn't be "Sad" if they didn't already do it, and I would in fact be pleasantly surprised. Which is why I'm asking the question.

EDIT: Turns out you're right! https://msdn.microsoft.com/en-us/library/office/bb687899.asp...