Performance is one of the non-functional requirements (NFR) for IT systems.
We tend to think that performance has to be very high.
In general, yes. But not always. As it is a very important driver, the
bottom line is that performance has to be good enough.
In Poland we have the banking system Elixir that runs sessions 3 times per
day, Monday – Friday. So if you set your money transfer from one bank to
another on Friday afternoon, the money will be delivered on Monday. So the
performance of your system could be low, as long as it calculates
everything before a session.
So from this example it is clear that performance has to be a well
understood driver, and not always very high. Sometimes a good enough
performance is needed.