My computer RTC is quite accurate as computer clocks go, being
off by no more than a few seconds over a period of several days
without syncing, whereas I've noticed some computers to be off by
minutes in 24 hours even with a healthy battery.

I've heard that the accuracy of a computer clock not only depends
on the oscillator in the RTC hardware, but is also influenced by
interrupt calls (or something like that) in OS and app
environment. If this is true, do I just happen to have a good RTC
hardware or does my OS and software installation also have
something to do with it?