View Full Version : Clock gets slower

17-09-2003, 08:11 AM
Every 4 or so days i will put the clock in the bottom right-hand corner to to the correct time, but then in 4 or so days later it will become around about 15 minutes slower..what causes this and what needs updating..(CMOS?)

17-09-2003, 08:24 AM
Hi ya - I had the same problem (wind XP home) but mine was slowing daily until I got service pack 1

regards Bug :)

Terry Porritt
17-09-2003, 08:38 AM
Usually the cause of this is the CMOS battery running down. Even though they only supply a minute current to the cmos chips they do eventually expire.
I suppose a software bug could also have funny effects too.

Graham L
17-09-2003, 05:32 PM
Not necessarily "bugs"; just rottten programming can do it. :D The OS's time relies on the CPU having time to deal with an interrupt which happens 18.2 times a second. If it misses some of these interrupts, the time counter doesn't get increased, so the time gets "slower".

The usual cause is a low battery which causes the crystal oscillator to slow down. Of course there are crsytals which are high or low in frequency right from new. Some AT boards had a trimmer capacitor so you could adjust the clock to be exacly right. I don't think they do that now. :D