I'd like a more reasonable refresh interval for plasma-systemmonitor. Currently it updates at about half a second or less. Or as the "Minimum time between updates" setting says: "No limit".

Fast graphical refresh intervals are a well known way to get an application to use too much CPU, and this issue becomes even worse in conjunction with https://bugs.kde.org/show_bug.cgi?id=429152 (Graphs can consume excessive CPU resources on platforms with weak Intel GPUs and high-resolution displays).

A system monitor should be lightweight and quick to process, and thus reliable when the machine is under stress, it shouldn't be using as many hardware resources as it does.

The default should be something more reasonable, probably something between the range of 1s to 2s.

1.5s is probably the best compromise.