It varies quite a lot depending on the exact project and how much is expected to be purely waiting on one big compute job to finish. For something like climate

It varies quite a lot depending on the exact project and how much is expected to be purely waiting on one big compute job to finish. For something like climate simulations where a project is running big long jobs repeatedly I imagine they spend quite a bit of time on making it fast. For something like detector development where you run the hardware simulation production once and then spend three years trying to find the best way to reconstruct events less effort is put into making it fast. Saving two months from a six months job you run once isn't worth it if you have to spend more than a few weeks optimising it, and as these type of jobs need to write a lot to disk there's a limit to how much you'll get from optimising the hot loop.