On Tue, 11 Aug 2009 10:45:42 +0000 (UTC), root
wrote:

The damned thing loses about 20 minutes/day and has
so since the machine was new about 3 years ago.

Well, that's:
20/1440 = 1.4% accuracy

My guess is that it isn't fixable, but maybe you
have some ideas.

Any particular maker, model, motherboard model?

I've seen the same problem on various machines over the years. On
servers, the problem became sufficiently critical to impliment a fix.
I measured the frequency of the common 14.31818 MHz crystal feeding
the clock oscillator and found it to vary horribly with temperature. I
replaced the crystal with a somewhat better packaged oscillator:
http://parts.digikey.ie/1/1/67619-oscillator-14-31818mhz-full-mxo45t-2c-14m31818.html
That reduced the drift to tolerable levels. Modern motherboards use
different frequencies, but the same principle applies.

For a 14.31818Mhz oscillator to be off 1.4%, it would read about
14.5Mhz. Measure yours.

More difficult to fix are applications that steal clock cycles or beat
up on the processor sufficiently that it misses interrupts. On my old
Pentium III desktop, playing DVD videos was the worst culprit. I also
found some CPU benchmark programs that intentionally made the
processor very busy (and very hot) that ate CPU cycles. I can't offer
any suggestions without knowing the hardware, the system, and the
software mix.

There was also a problem with some old Dell machines, where the BIOS
and the OS were fighting each other for control of the clock. There
was a fix, but I'm too lazy to look for it.

One machine I worked with had a unique problem. When the machine went
into standby, the clock would just stop. When it came out of standby,
it would continue where it left off, losing the time it was in
standby. It was fixed under warranty. I don't recall the vendor.

Oh yeah, check the button battery that backs up the clock. It might
be dead or dying.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558