On 11 May 00, at 15:24, ENIO SCHUTT JUNIOR wrote:
> I have seen people talking about overclocking and so on.
> I guess that prime95 really stresses a lot any kind of system.
Yes! Though a correctly assembled system with all parts running at
their rated voltage, speed & temperature should not be _over_stressed
by Prime95, or for that matter by any other application.
> What about if in a new version there would be an option to
> set the maximum percentual of the processor's usage? or maybe
> some time limit per day?
The first idea cannot be implemented in any application running under
a sane operating system - or even many insane OSes! - though you
could probably get an approximate 50% duty cycle by running a "do
nothing" compute loop avoiding the FPU as a seperate process at the
same priority as Prime95 - or setting the priority of Prime95 to 0,
so that the system idle process steals cycles from it. The point is
that an operating system must always allocate all the CPU cycles
available (except those used to do make the process scheduling
decisions) to some process or other.
The second idea is already possible - but the problem is that a
system with a cache or FPU overheating due to overclocking (or a
cooling problem like a broken fan) is probably going to take only
seconds to get dangerously warm.
> or even a time limit in which prime95
> reaches 100%, then getting to a lower percentual... lets say
> 75%.
You _may_ be able to set this in your system BIOS. Enable CPU
overheat warning, set the overheat duty cycle appropriately (the
default setting is usually 50% or 62.5%) and then set the CPU
overheat detection temperature so that your system normally runs
believing it's overheating. Not all BIOSes support this; not all
motherboards have the neccessary temperature sensors fitted, and some
that do will insist on sounding a warning (via the system speaker) if
an overheat condition is detected.
But the real problem with all these methods is that you are throwing
processor cycles away trying to keep the damn thing cool. Why not
simply reduce or remove the overclocking instead? The point is that
if the stress imposed by Prime95 is too much for the system (in an
overclocked state), then almost certainly some combination of other
programs you run will also be too much. If you really _must_ keep
your overclocking, try fitting an extra case fan, and/or arrange
ducting so that the processor fan receives cool air from outside the
system case instead of recycling warm air already "trapped" inside.
These tactics could be enough to make Prime95 run reliably whilst
retaining the high clock speed.
Regards
Brian Beesley
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