crp at cmc.net
Wed Jan 7 00:50:07 UTC 2009
> Ray Parrish wrote:
>> Derek Broughton wrote:
>>> Ray Parrish wrote:
>>>> Well, as I said above I'm not worried about the extra power the "cpu"
>>>> not the whole desktop takes... The cpu is just a small chip inside the
>>>> box, and runs on 5 volts. Reading comprehension my friend...
>>> Electricity comprehension my friend. 5V or 500V is (largely) irrelevant -
>>> it's the power, not the voltage.
>> Ok, I did some research, and this supports my view [From Wikipedia]
>>> Dynamic frequency scaling reduces the number of instructions a
>>> processor can issue in a given amount of time, thus reducing
>>> performance. Hence, it is generally used when the workload is not
>>> Dynamic frequency scaling by itself is rarely worthwhile as a way to
>>> conserve switching power. Saving the most power requires dynamic
>>> voltage scaling too, because of the V^2 component and the fact that
>>> modern CPUs are strongly optimized for low power idle states. In most
>>> constant-voltage cases it is more efficient to run briefly at peak
>>> speed and stay in a deep idle state for longer (called "race to
>>> idle"), than it is to run at a reduced clock rate for a long time and
>>> only stay briefly in a light idle state. However, reducing voltage
>>> along with clock rate can change those tradeoffs.
>> Article url below -
>> However, it uses more power than I thought as shown in the following quote -
>> "Sempron 3400+ has a die size of 84mm^2 , produced on AMD's 90-nanometer
>> silicon-on-insulator (SOI) process. It runs at 2.0GHz and features a
>> 256KB L2 cache, and its max thermal power is 62 watts. "
>> From the following page -
>> So, although I'm not really using more power by setting my cpu scaling
>> to Performance, it still uses more power than I thought.
>> Later, Ray Parrish
> >From another viewpoint: My situation requires my computer to be
> inside an enclosed space without a great deal of ventilation. With
> scaling my cpu runs at 1.3 ghz and about 48 degrees C and the gpu is
> 58. At full speed the temperature of the cpu raises to about 58
> degrees. If I go to windows and play something like Crysis or Fallout
> 3 I have to keep the cabinet door open to prevent the computer from
> crashing. I can't check the speed or temp very easily but when I
> reboot to Ubuntu the cpu is running over 60 degrees and the gpu is
> over 65 degrees. Also everything is running from batteries so power
> matters to me.
That's pretty hot! I converted your celsius numbers to fahrenheit, and
48 C is 118 F. My computer purrs along at 104 F, and during a four hour
virus scan of my Windows install, with the cpu maxed out the whole time,
it never got over 107 F...
I very seldom play games, so I don't know how it would perform under
Later, Ray Parrish--
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