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underclocking

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May 30, 2004 6:24:41 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Hi all. I have a weird experiment I want to do which involves underclocking.
Anyone know how much underclocking can be done on a cpu and if it can damage
it like overclocking will do. I have a 2600XP running a 1.9ghz 333FSB 1.65V
stock. Can I lower this thing to like 100FSB with a voltage of 1.5V without
damaging the cpu. What are the effects of underclocking. I'm gussing there
might be some stability problems to some point but will it damage the cpu.
please advise
Thanks to all.

More about : underclocking

Anonymous
a b K Overclocking
a b à CPUs
May 30, 2004 11:17:57 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Frank wrote:

> Hi all. I have a weird experiment I want to do which involves underclocking.
> Anyone know how much underclocking can be done on a cpu and if it can damage
> it like overclocking will do. I have a 2600XP running a 1.9ghz 333FSB 1.65V
> stock. Can I lower this thing to like 100FSB with a voltage of 1.5V without
> damaging the cpu. What are the effects of underclocking. I'm gussing there
> might be some stability problems to some point but will it damage the cpu.
> please advise
> Thanks to all.
>
>

Underclocking will not hurt a thing.

You're mixing terms, however with the 333 and 100 FSB designations. When
AMD speaks of the FSB being 333 they are talking about the data rate. The
data rate is 2x the clock, however so the bus clock, for a 333Mhz Bus, is
166.7MHz.

The 100MHz you speak of would have to be the clock because that's the
slowest clock on Athlon/Duron motherboards, which is a 200MHz Bus.

Too low a voltage and it simply won't run, but 1.5 isn't so low that we can
automatically write it off and their mobiles run down there so there's a
good chance that will work, especially with the slower speed.

As for power, it varies linearly with speed and with the square of the
voltage so, if we assume '0' at 0 MHz and '0' voltage (both unreal numbers
but perhaps good enough for a rough estimate), you should get about a 40%
reduction from the speed lowering (1-[100/166.7]) and another 17% from the
lower voltage (1-[V1^2/V2^2]). Your XP2600+ has a rated max power of 68.3
watts so 68.3*(100/166.7) is 41 watts and then 41* (1.5^2/1.65^2) is about
34 watts for your max power dissipation. Typical at 2600+ is 53.7 so,
applying the same ratios, we get about 27 watts for your underclocked
'typical'.

Someone suggested you might be able to do with removing the fan from your
heatsink. No way unless you have a case sized heatsink right under the case
fan.

For comparison, an Intel 1 Gig P3 has a thermal design power of 26 to 29
watts, depending on the stepping, and you sure as heck wouldn't try running
one of those with no fan.

So, to summarize, your XP would be running 1.15 gig (11.5 multiplier) from
an FSB clock of 100MHz, for a 200MHz data rate, with an estimated max power
dissipation, using 1.5V Vcore, of 34 watts and typically around 27 watts
(we guess).

Now, in reality, there is some static power consumption even when the clock
is not running so, to be on the safe side, I'd add another 5 to 8 watts to
those estimates to compensate for the '0' offset in the rough calculation.
Anonymous
a b K Overclocking
a b à CPUs
May 30, 2004 11:43:41 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

> Anyone know how much underclocking can be done on a cpu and if it can damage
> it like overclocking will do.

I think that underclocking a processor will do no damage whatsoever, and
might even increase the life of your CPU

> I have a 2600XP running a 1.9ghz 333FSB 1.65V
> stock. Can I lower this thing to like 100FSB with a voltage of 1.5V without
> damaging the cpu. What are the effects of underclocking. I'm gussing there
> might be some stability problems to some point but will it damage the cpu.

I personally have never tried it - I want performance out of my PC. It
should not damage your CPU at all - the worst that can happen is that it
doesn't start because the processor needs more volts, and that is a
temporary problem, fixed by clearing the CMOS.

Bear in mind that semiconductors need at least a certain voltage to
function - something about band gaps and bias voltages. 1.5V should be
adequate, though.

Default for your athlon is 166FSB, actually - it is DDR memory, so take
that into account. Bringing your FSB down to 100 will result in an
Athlon XP 1560+ (if the same naming scheme holds and the numbers are
linear). It will be a 1.14 GHz processor - reminds me of the days of the
very first, Pentium III-busting Athlon....

It will also run cooler and last a lot longer then the Athlon of that
day, but don't be tempted to take the heatsink off, as it could quite
literally melt down. You might be able to take the fan off - but check
the temperatures under load and while idling first.

Good luck, though.
Related resources
May 30, 2004 11:43:42 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

I know my pc will be very slow compared to what it should be by default. I'm
not planning on underclocking my cpu for everyday life, just as an
experiment I want to do for my own sake involving temps and noise.
Thanks for the info BananaOfTheNight

"BananaOfTheNight" <bananaofthenight@hotmail.com.nospaam.please> wrote in
message news:c9da0n$piq$1@pegasus.csx.cam.ac.uk...
> > Anyone know how much underclocking can be done on a cpu and if it can
damage
> > it like overclocking will do.
>
> I think that underclocking a processor will do no damage whatsoever, and
> might even increase the life of your CPU
>
> > I have a 2600XP running a 1.9ghz 333FSB 1.65V
> > stock. Can I lower this thing to like 100FSB with a voltage of 1.5V
without
> > damaging the cpu. What are the effects of underclocking. I'm gussing
there
> > might be some stability problems to some point but will it damage the
cpu.
>
> I personally have never tried it - I want performance out of my PC. It
> should not damage your CPU at all - the worst that can happen is that it
> doesn't start because the processor needs more volts, and that is a
> temporary problem, fixed by clearing the CMOS.
>
> Bear in mind that semiconductors need at least a certain voltage to
> function - something about band gaps and bias voltages. 1.5V should be
> adequate, though.
>
> Default for your athlon is 166FSB, actually - it is DDR memory, so take
> that into account. Bringing your FSB down to 100 will result in an
> Athlon XP 1560+ (if the same naming scheme holds and the numbers are
> linear). It will be a 1.14 GHz processor - reminds me of the days of the
> very first, Pentium III-busting Athlon....
>
> It will also run cooler and last a lot longer then the Athlon of that
> day, but don't be tempted to take the heatsink off, as it could quite
> literally melt down. You might be able to take the fan off - but check
> the temperatures under load and while idling first.
>
> Good luck, though.
Anonymous
a b K Overclocking
a b à CPUs
May 31, 2004 6:22:02 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Why not begin by lowering the CPU core voltage bit by bit. If you can
overclock a CPU, it is because it has extra performance headroom that
overclocking can use. Conversely, you can likely reduce the core voltage
while keeping the clock speed the same, using performance headroom to get a
cooler running CPU at the rated speed, or a lower flow of air for the same
CPU temperature.


Underclocking will not damage the CPU, niether will overclocking. Raising
the core voltage unreasonabally high WILL destroy the CPU in a heartbeat.
Having the heatsink fall off, whether your CPU is underclocked or
overclocked, can destroy AMD CPU's that don't have implementation of the
catastrophic overheating stop function.


--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."


"Frank" <Frankheon@hotmail.com> wrote in message
news:4cuuc.11164$Ca5.385698@wagner.videotron.net...
> I know my pc will be very slow compared to what it should be by default.
I'm
> not planning on underclocking my cpu for everyday life, just as an
> experiment I want to do for my own sake involving temps and noise.
> Thanks for the info BananaOfTheNight
>
> "BananaOfTheNight" <bananaofthenight@hotmail.com.nospaam.please> wrote in
> message news:c9da0n$piq$1@pegasus.csx.cam.ac.uk...
> > > Anyone know how much underclocking can be done on a cpu and if it can
> damage
> > > it like overclocking will do.
> >
> > I think that underclocking a processor will do no damage whatsoever, and
> > might even increase the life of your CPU
> >
> > > I have a 2600XP running a 1.9ghz 333FSB 1.65V
> > > stock. Can I lower this thing to like 100FSB with a voltage of 1.5V
> without
> > > damaging the cpu. What are the effects of underclocking. I'm gussing
> there
> > > might be some stability problems to some point but will it damage the
> cpu.
> >
> > I personally have never tried it - I want performance out of my PC. It
> > should not damage your CPU at all - the worst that can happen is that it
> > doesn't start because the processor needs more volts, and that is a
> > temporary problem, fixed by clearing the CMOS.
> >
> > Bear in mind that semiconductors need at least a certain voltage to
> > function - something about band gaps and bias voltages. 1.5V should be
> > adequate, though.
> >
> > Default for your athlon is 166FSB, actually - it is DDR memory, so take
> > that into account. Bringing your FSB down to 100 will result in an
> > Athlon XP 1560+ (if the same naming scheme holds and the numbers are
> > linear). It will be a 1.14 GHz processor - reminds me of the days of the
> > very first, Pentium III-busting Athlon....
> >
> > It will also run cooler and last a lot longer then the Athlon of that
> > day, but don't be tempted to take the heatsink off, as it could quite
> > literally melt down. You might be able to take the fan off - but check
> > the temperatures under load and while idling first.
> >
> > Good luck, though.
>
>
May 31, 2004 3:04:07 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

"David Maynard" <dNOTmayn@ev1.net> wrote in message
news:10bkue089j8brc8@corp.supernews.com...
> Frank wrote:
>
> > Hi all. I have a weird experiment I want to do which involves
underclocking.
> > Anyone know how much underclocking can be done on a cpu and if it can
damage
> > it like overclocking will do. I have a 2600XP running a 1.9ghz 333FSB
1.65V
> > stock. Can I lower this thing to like 100FSB with a voltage of 1.5V
without
> > damaging the cpu. What are the effects of underclocking. I'm gussing
there
> > might be some stability problems to some point but will it damage the
cpu.
> > please advise
> > Thanks to all.
> >
> >
>
> Underclocking will not hurt a thing.

It would hurt my pride!! :) 


> You're mixing terms, however with the 333 and 100 FSB designations. When
> AMD speaks of the FSB being 333 they are talking about the data rate. The
> data rate is 2x the clock, however so the bus clock, for a 333Mhz Bus, is
> 166.7MHz.
>
> The 100MHz you speak of would have to be the clock because that's the
> slowest clock on Athlon/Duron motherboards, which is a 200MHz Bus.
>
> Too low a voltage and it simply won't run, but 1.5 isn't so low that we
can
> automatically write it off and their mobiles run down there so there's a
> good chance that will work, especially with the slower speed.
>
> As for power, it varies linearly with speed and with the square of the
> voltage so, if we assume '0' at 0 MHz and '0' voltage (both unreal numbers
> but perhaps good enough for a rough estimate), you should get about a 40%
> reduction from the speed lowering (1-[100/166.7]) and another 17% from the
> lower voltage (1-[V1^2/V2^2]). Your XP2600+ has a rated max power of 68.3
> watts so 68.3*(100/166.7) is 41 watts and then 41* (1.5^2/1.65^2) is about
> 34 watts for your max power dissipation. Typical at 2600+ is 53.7 so,
> applying the same ratios, we get about 27 watts for your underclocked
> 'typical'.
>
> Someone suggested you might be able to do with removing the fan from your
> heatsink. No way unless you have a case sized heatsink right under the
case
> fan.
>
> For comparison, an Intel 1 Gig P3 has a thermal design power of 26 to 29
> watts, depending on the stepping, and you sure as heck wouldn't try
running
> one of those with no fan.
>
> So, to summarize, your XP would be running 1.15 gig (11.5 multiplier) from
> an FSB clock of 100MHz, for a 200MHz data rate, with an estimated max
power
> dissipation, using 1.5V Vcore, of 34 watts and typically around 27 watts
> (we guess).
>
> Now, in reality, there is some static power consumption even when the
clock
> is not running so, to be on the safe side, I'd add another 5 to 8 watts to
> those estimates to compensate for the '0' offset in the rough calculation.
>
>
May 31, 2004 9:35:32 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Great info, thanks all.
Now lets experiment ;o)

"David Maynard" <dNOTmayn@ev1.net> wrote in message
news:10bkue089j8brc8@corp.supernews.com...
> Frank wrote:
>
> > Hi all. I have a weird experiment I want to do which involves
underclocking.
> > Anyone know how much underclocking can be done on a cpu and if it can
damage
> > it like overclocking will do. I have a 2600XP running a 1.9ghz 333FSB
1.65V
> > stock. Can I lower this thing to like 100FSB with a voltage of 1.5V
without
> > damaging the cpu. What are the effects of underclocking. I'm gussing
there
> > might be some stability problems to some point but will it damage the
cpu.
> > please advise
> > Thanks to all.
> >
> >
>
> Underclocking will not hurt a thing.
>
> You're mixing terms, however with the 333 and 100 FSB designations. When
> AMD speaks of the FSB being 333 they are talking about the data rate. The
> data rate is 2x the clock, however so the bus clock, for a 333Mhz Bus, is
> 166.7MHz.
>
> The 100MHz you speak of would have to be the clock because that's the
> slowest clock on Athlon/Duron motherboards, which is a 200MHz Bus.
>
> Too low a voltage and it simply won't run, but 1.5 isn't so low that we
can
> automatically write it off and their mobiles run down there so there's a
> good chance that will work, especially with the slower speed.
>
> As for power, it varies linearly with speed and with the square of the
> voltage so, if we assume '0' at 0 MHz and '0' voltage (both unreal numbers
> but perhaps good enough for a rough estimate), you should get about a 40%
> reduction from the speed lowering (1-[100/166.7]) and another 17% from the
> lower voltage (1-[V1^2/V2^2]). Your XP2600+ has a rated max power of 68.3
> watts so 68.3*(100/166.7) is 41 watts and then 41* (1.5^2/1.65^2) is about
> 34 watts for your max power dissipation. Typical at 2600+ is 53.7 so,
> applying the same ratios, we get about 27 watts for your underclocked
> 'typical'.
>
> Someone suggested you might be able to do with removing the fan from your
> heatsink. No way unless you have a case sized heatsink right under the
case
> fan.
>
> For comparison, an Intel 1 Gig P3 has a thermal design power of 26 to 29
> watts, depending on the stepping, and you sure as heck wouldn't try
running
> one of those with no fan.
>
> So, to summarize, your XP would be running 1.15 gig (11.5 multiplier) from
> an FSB clock of 100MHz, for a 200MHz data rate, with an estimated max
power
> dissipation, using 1.5V Vcore, of 34 watts and typically around 27 watts
> (we guess).
>
> Now, in reality, there is some static power consumption even when the
clock
> is not running so, to be on the safe side, I'd add another 5 to 8 watts to
> those estimates to compensate for the '0' offset in the rough calculation.
>
>
!