[mythtv-users] silent and low-power: AMD or Intel?

[Brian Wood]

On Wednesday 27 May 2009 18:20:40 John Drescher wrote:
> > When you lower the CPU frequency, the external data bus isn't slowed
> > down (unlike AMD for example). So the overall system continues to
> > operate at the same speed.
>
> The external bus stays the same speed with an AMD chip. The internal
> clock and the voltage the processor uses both reduce however.

There may be a difference between a CPU at idle and one working fairly hard. 
Since most scaling schemes only clock down when the CPU is idle this may be 
moot.

Intuitively it would seem that lowering the voltage and the clock should 
reduce the power consumption, but if the CPU has to work longer in the 
reduced consumption mode, the total energy required to perform a specific 
task would probably stay pretty much the same.

There might also be a difference between scaling schemes designed to increase 
battery life for laptops and ones intended to reduce total consumption for a 
server.

It would help if there was some sort of "work per watthour" parameter for 
CPUs, but I'm not aware of any such thing.

Since vendor information is usually intended to sell product, and is thus 
somewhat obfuscated, it's not surprising there is so much confusion over the 
issue.

-- 
beww
beww at beww.org