"Grieken, Paul van" <[EMAIL PROTECTED]> writes:
> > Now I have a new pentium III 450MHz with windows 98 plus at
home I
> > wanted to run prime on it.
> > The fastest iteration was in 0.21 sec.
> > I turned the monitor off.
> > The power management was set to:
> > Computer never in standby
> > Disk drived off in 10 min.
> > Monitor off in 15 min.
> > When I switched the monitor on the next day I saw that the iterations
> > speed was dropped during the night to 1.2 sec.
> >
> > Why did this happen and how can I maintain the speed of 0.21 sec also
> > during the night, with of course as less power as possible.
Well, without examining your system setup I can't say for sure, but
it sounds like you have three different CPU modes: full power,
standby and sleep. In standby mode, the CPU will run at low
speed; in sleep mode, it will stop. It sounds as though the CPU
changed to standby mode.
Power management is confusing as it is set in two places: in the
system BIOS setup, and in the operating system. Different
systems have different methods for accessing the system BIOS
setup, something like pressing <F2> whilst the memory check is
running after switch-on or system reset. I don't run Windows 98
and therefore don't know exactly how to get at its power
management setup; in '95 use the "Power" option on the Control
Panel.
You have to let the CPU run full speed all the time in order for
Prime95 to run flat out. If the system clock is slowed in a power-
saving mode, then Prime95 will slow down. A speed drop of about
6x (from 0.2s to 1.2s) sounds about right.
Personally, on desktop systems, I do not allow the hard disk to
time out either. Starting the hard disk takes several seconds,
during which time the power draw is high, and the disk wears out if
the heads keep landing on the same zone when the disk spins
down. Modern hard disk drives have a low power consumption and
are designed to last decades in continuous use. They will almost
certainly fail sooner if used "intermittently". The story may be
different on portables when used on battery power, but I cannot see
any justification for allowing the disk drive on a desktop to time out.
If you're worried about pollution, CO2 emission etc., I could point
out that the environmental damage caused by producing one disk
drive is probably a lot greater than that caused by its consumption
of power during its lifetime.
Note that, by default, Prime95 writes save files every half hour. If
you set the disk drive timeout to 10 mins, you will save only 2/3 of
the miserly consumption, but you will get at least two disk drive
start/stop/temperature cycles per hour, which I would suggest
might cause rapid aging.
Allow monitors to go into standby modes, by all means, but I prefer
to physically switch them off. This reduces their "idle" power
consumption from approx. 7W to zero, and also greatly reduces
the risk of fire. Due to their construction and the requirement for
high tension to make the cathode ray tube operate, monitors (like
TV sets) are thousands of times more likely to start a fire than any
other part of a computer system, even whilst in standby mode.
Mind you, the risk is, at most, small.
Finally, give some consideration as to where the computer is sited.
If you put it somewhere that usually needs heating, then the
"waste" heat from an operating computer system can actually cut
your heating bill. Conversely, if you put it somehere that usually
needs cooling (air conditioning), the extra power cost is magnified
since the air con will have to work harder to dump the extra waste
heat.
Regards
Brian Beesley
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