The system clock of my PC (not a laptop) runs behind. What could be the cause?
Best Answer
Your CMOS battery that maintains the BIOS (and clock) information could have run out. Change it, it is usually a CR2032 battery and really easy to swap out on your motherboard.
No way to do it with the native clock. Try TClock Light, it looks a lot like the built-in one but with a lot more options.
Edit: Apparently it doesn't work great on Vista, but the version discussed here apparently does. The download and install information is at the bottom of that page. The guy is rather verbose.
Yes there are these two clocks. The RTC (aka CMOS Clock/ Hardware Clock) as you referred, and the System Clock (aka Kernel Clock, Software Clock) whose value is saved in the OS config. This system clock is based on Timer Interrupts.
And as is obvious these two may some fractional offset due to which they will deviate and the OS has multiple strategies to deal with the timer drift. One of the common modern ways to keep both in sync using a Time Server like time.windows.com based on the Network Time protocol.
Best Answer
Your CMOS battery that maintains the BIOS (and clock) information could have run out. Change it, it is usually a CR2032 battery and really easy to swap out on your motherboard.