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How many watts for athlon t'bred



 
 
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  #1  
Old October 12th 04, 11:40 AM
Gareth Tuckwell
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Default How many watts for athlon t'bred

I am doing some heat calculations:

How many watts (power not heat!) does my Athlon 2400+ Thoroughbred require /
use at standard clock + volt settings? I think I read 60 watts somewhere,
but I don't recall where. I also know this info is on the AMD website
somewhere, but I haven't time to look right now and someone here probably
knows already!

Thanks.


  #2  
Old October 12th 04, 12:42 PM
Chip
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"Gareth Tuckwell" wrote in message
...
I am doing some heat calculations:

How many watts (power not heat!)


What do you mean by that? Power = Heat. Its the same thing.

Chip


  #3  
Old October 12th 04, 02:06 PM
iTsMeMa
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Default

Listed as "Maximum Theoretical Power"

XP2400 TBred Low voltage model 65.3W
XP2400 TBred 68.3W
XP2400 Thorton 68.3W

Garry.


"Gareth Tuckwell" wrote in message
...
I am doing some heat calculations:

How many watts (power not heat!) does my Athlon 2400+ Thoroughbred require

/
use at standard clock + volt settings? I think I read 60 watts somewhere,
but I don't recall where. I also know this info is on the AMD website
somewhere, but I haven't time to look right now and someone here probably
knows already!

Thanks.




  #4  
Old October 12th 04, 02:11 PM
Chip
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Posts: n/a
Default


"iTsMeMa" wrote in message
...
Listed as "Maximum Theoretical Power"

XP2400 TBred Low voltage model 65.3W
XP2400 TBred 68.3W
XP2400 Thorton 68.3W

Garry.


Assuming you don't overclock, of course. In which case it can easily be
circa 100w

Chip


  #5  
Old October 12th 04, 02:58 PM
Gareth Tuckwell
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Posts: n/a
Default

"Chip" wrote in message
...

"iTsMeMa" wrote in message
...
Listed as "Maximum Theoretical Power"

XP2400 TBred Low voltage model 65.3W
XP2400 TBred 68.3W
XP2400 Thorton 68.3W

Garry.


Assuming you don't overclock, of course. In which case it can easily be
circa 100w

Chip


Thanks guys - I am currently undervolting my athlon (using standard 133x15)
and I was trying to figure out if dropping the volts from 1.65 ro 1.5 would
actually generate significantly less heat or not!

I figure that at 2000Mhz power usage is (as above) 68.3W, but dropping from
1.65v to 1.5v reduces power intake to 56.4W - 17.5% less power, therefore
17.5% less heat generated. Does this sound reasonable? I don't have exact
temperatues readings before and after, because I have been messing with the
fans and the case to quieten things down + improve airflow at the same time!
I have new quiet PSU and a quiet Samsung drive. I now use just 2 fans
(rewired to 5v) blowing air around in the case. Air is sucked in past my
graphics card passive heatsink (radeon 8500), it then floats around for a
while and is finally blown by 2 fans through my zalman flower cooler and out
through a new hole in the case next to the processor. It reaches mid to high
40s under load - I can't get it over 50 degrees and I only have 2 silent
fanes running, so I am happy with that! Previously it would reach 55+ under
load, but I don't know if it is the voltage drop or the new fan layout that
is helping (probably both). I will continue to experiment in my spare time
(working at the moment!).

I could draw outside air in through the processor cooler, then out via the
graphics card, but on exiting the case, the hot air would rise, then be
drawn back into the processor cooler! I know I could put an intake fan on
the front to bring cool air from the front of the machine, then add another
fan to blow (some) air over the grapics card and out the back, but that
means 2 more fans + more noise. I might consider adding a fan at the front,
ducting the air to the graphics card and leave it to pump out through the
processor, but that requires time + some kind of duct!!


  #6  
Old October 12th 04, 03:51 PM
iTsMeMa
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Posts: n/a
Default

Regarding undervolting your CPU, I have been down that path. My XP2400 on a
KT133A board was easy to undervolt to 1.5v. It did indeed reduce temps
approx. 5 - 7 degrees C. However, I noticed occasionally a minor twitch if I
was pushing the proc (with whatever program) With my current setup (K7V88
and XP2400) undervolting - without mod - is not possible. Just had to learn
to live with temps 2 - 3 degrees higher. :}

Best of luck,

Garry.

"Gareth Tuckwell" wrote in message
...
"Chip" wrote in message
...

"iTsMeMa" wrote in message
...
Listed as "Maximum Theoretical Power"

XP2400 TBred Low voltage model 65.3W
XP2400 TBred 68.3W
XP2400 Thorton 68.3W

Garry.


Assuming you don't overclock, of course. In which case it can easily be
circa 100w

Chip


Thanks guys - I am currently undervolting my athlon (using standard
133x15) and I was trying to figure out if dropping the volts from 1.65 ro
1.5 would actually generate significantly less heat or not!

I figure that at 2000Mhz power usage is (as above) 68.3W, but dropping
from 1.65v to 1.5v reduces power intake to 56.4W - 17.5% less power,
therefore 17.5% less heat generated. Does this sound reasonable? I don't
have exact temperatues readings before and after, because I have been
messing with the fans and the case to quieten things down + improve
airflow at the same time! I have new quiet PSU and a quiet Samsung drive.
I now use just 2 fans (rewired to 5v) blowing air around in the case. Air
is sucked in past my graphics card passive heatsink (radeon 8500), it then
floats around for a while and is finally blown by 2 fans through my zalman
flower cooler and out through a new hole in the case next to the
processor. It reaches mid to high 40s under load - I can't get it over 50
degrees and I only have 2 silent fanes running, so I am happy with that!
Previously it would reach 55+ under load, but I don't know if it is the
voltage drop or the new fan layout that is helping (probably both). I will
continue to experiment in my spare time (working at the moment!).

I could draw outside air in through the processor cooler, then out via the
graphics card, but on exiting the case, the hot air would rise, then be
drawn back into the processor cooler! I know I could put an intake fan on
the front to bring cool air from the front of the machine, then add
another fan to blow (some) air over the grapics card and out the back, but
that means 2 more fans + more noise. I might consider adding a fan at the
front, ducting the air to the graphics card and leave it to pump out
through the processor, but that requires time + some kind of duct!!



  #7  
Old October 12th 04, 04:15 PM
Gareth Tuckwell
external usenet poster
 
Posts: n/a
Default

"iTsMeMa" wrote in message
...
Regarding undervolting your CPU, I have been down that path. My XP2400 on
a KT133A board was easy to undervolt to 1.5v. It did indeed reduce temps
approx. 5 - 7 degrees C. However, I noticed occasionally a minor twitch if
I was pushing the proc (with whatever program) With my current setup
(K7V88 and XP2400) undervolting - without mod - is not possible. Just had
to learn to live with temps 2 - 3 degrees higher. :}


I have actually just realised I have been running it at 1.475v for several
days now, of course, as soon as I posted that message it crashed!!
Coincidence? Maybe!

I must say though - the hardware monitor (windows) was reporting 1.503v at a
BIOS setting of 1.475v. Anyone know why the hardware monitor (motherboard
manufacturer software) reports a higher voltage than I set in the BIOS (same
for all voltages)? The other voltages 12v, 3v, 5v etc are not absolutely
spot on either, but I know power supplies have tolerance levels, but I would
expect the CPU voltage would to run at what it is set in the BIOS?? Anyone
notice this?


  #8  
Old October 12th 04, 05:34 PM
Steve Wolfe
external usenet poster
 
Posts: n/a
Default

Thanks guys - I am currently undervolting my athlon (using standard
133x15)
and I was trying to figure out if dropping the volts from 1.65 ro 1.5

would
actually generate significantly less heat or not!


1.5/1.65=0.909, so you can figure on about an 11% reduction in heat.

I figure that at 2000Mhz power usage is (as above) 68.3W, but dropping

from
1.65v to 1.5v reduces power intake to 56.4W - 17.5% less power, therefore
17.5% less heat generated. Does this sound reasonable?


It does. Not that the two numbers don't match up (11% vs. 17.5%) because
the 17.5% number obtained by comparing the theoretical maximum value to a
real-world value. Had you measured the real-world usage before and after,
the difference should be much closer to 11%.

If you really wanted lower power, you could go with a mobile Athlon XP,
where the max power draws can be as low as 35 watts, and the "power now"
featured (I believe there's at least one desktop board that supports it)
will keep actual draws much, much lower when not under load. However, it
does sound like you've done an outstanding job with what you've got!

steve


  #9  
Old October 12th 04, 05:37 PM
Chip
external usenet poster
 
Posts: n/a
Default


"Gareth Tuckwell" wrote in message
...
"iTsMeMa" wrote in message
...
Regarding undervolting your CPU, I have been down that path. My XP2400 on
a KT133A board was easy to undervolt to 1.5v. It did indeed reduce temps
approx. 5 - 7 degrees C. However, I noticed occasionally a minor twitch
if I was pushing the proc (with whatever program) With my current setup
(K7V88 and XP2400) undervolting - without mod - is not possible. Just had
to learn to live with temps 2 - 3 degrees higher. :}


I have actually just realised I have been running it at 1.475v for several
days now, of course, as soon as I posted that message it crashed!!
Coincidence? Maybe!

I must say though - the hardware monitor (windows) was reporting 1.503v at
a BIOS setting of 1.475v. Anyone know why the hardware monitor
(motherboard manufacturer software) reports a higher voltage than I set in
the BIOS (same for all voltages)? The other voltages 12v, 3v, 5v etc are
not absolutely spot on either, but I know power supplies have tolerance
levels, but I would expect the CPU voltage would to run at what it is set
in the BIOS?? Anyone notice this?


Yes, its very common. The calibration of the temperature monitoring chips -
and how they interact with the monitoring software - can be pretty poor.
The bios is perhaps better, but not much. The only real way to be sure is
to get out your voltmeter. If the 3.3v, 5v and 12v rails look right, you
can be fairly sure the others will be OK too.

Just as an aside, I ran my old Barton 3200+ at 1.2v at 11x133MHz for a while
with a Thermalright Silent Boost heatsink with the fan unplugged. It ran no
probs at all. 1.1v caused instant Blue Screen of Death.

Chip


  #10  
Old October 12th 04, 06:08 PM
Chip
external usenet poster
 
Posts: n/a
Default


"Steve Wolfe" wrote in message
...
Thanks guys - I am currently undervolting my athlon (using standard

133x15)
and I was trying to figure out if dropping the volts from 1.65 ro 1.5

would
actually generate significantly less heat or not!


1.5/1.65=0.909, so you can figure on about an 11% reduction in heat.


I would think it would be more than 11%. For the purposes of heat
dissipation we can consider the CPU to be a resistive load. And since P =
V**2/R, a reduction from 1.65 to 1.5 will yield a 1.5**2/1.65**2 reduction
in heat. Which is 17.4% Of course the CPU is not purely resistive, but
this is still a good approximation.

I figure that at 2000Mhz power usage is (as above) 68.3W, but dropping

from
1.65v to 1.5v reduces power intake to 56.4W - 17.5% less power, therefore
17.5% less heat generated. Does this sound reasonable?


It does. Not that the two numbers don't match up (11% vs. 17.5%) because
the 17.5% number obtained by comparing the theoretical maximum value to a
real-world value. Had you measured the real-world usage before and after,
the difference should be much closer to 11%.


Or 17.4% in fact.

If you really wanted lower power, you could go with a mobile Athlon XP,
where the max power draws can be as low as 35 watts, and the "power now"
featured (I believe there's at least one desktop board that supports it)
will keep actual draws much, much lower when not under load. However, it
does sound like you've done an outstanding job with what you've got!


The mobiles are good chips, but they only use less power because they run at
lower voltage, and you can always run a normal XP at lower voltage too. As
I said in another post, I ran a Barton 3200+ at 1500MHz at only 1.2v with no
heatsink fan for a couple of months without problem.

Chip


 




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