Why doesn Stopwatch show tenths or hundredths of a second by default?
Smartphones have two different clocks inside. The first is the normal clock that keeps track of the current date and time – this is the timer used by default, but on most Smartphones it only provides full seconds, not tenths or hundredths. We attempted to use a second “high resolution” timer that provides milliseconds, and is specified to be much more accurate than the first clock. To our surprise, on at least some Smartphones, this second clock is very inaccurate – it can be slow by as much as 10% when the phone is not on AC power, which means that Stopwatch could lose multiple minutes every hour. The inaccuracy seems to be related to the CPU load on the device, so is not predictable – otherwise we would be able to correct for it. When you turn on the High resolution timer option on the Stopwatch menu, this potentially inaccurate clock is used, which is why a warning pops up when you try to turn it on. Note that it is much more accurate when the phone is on AC power – we suspect becau
