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Re: Increasing minimum 'i386' processor



Hi,

On Mon, Nov 21, 2011 at 11:30:22PM +1100, Russell Coker wrote:
> On Mon, 21 Nov 2011, Patrick Schoenfeld <schoenfeld@debian.org> wrote:
> > well, its obvious that the absolute power consumption, which is what
> > you measure, has increased, given that the performance of the systems
> > has increased as well. 
> 
> If you are setting up a network of machines for bitcoin mining then it's most 
> likely that modern systems would give the best value for money.
> 
> > Measuring absolute values is all nice to compare the effective cost of
> > running a system, but it does neither support nor weaken the point that
> > modern systems are much better at power-saving.
> 
> If you have tasks which require little CPU power (such as a DNS server) and 
> the system is idle most of the time then comparing the idle power use is the 
> most important thing.

Uhm.. yes, its the "most important thing" for you to decide weither the system
is over-sized for a job that could eventually be very well be done by a atom
system or even some low performance embedded system.

However it does not qualify for a *general* assesment weither modern
systems have become better at power-saving or, because its still not
comparable. If you really do not need the extra power, you are still
able to buy a modern but less powerful system, like lets say an Atom.
You can compare that machines to draw a usefull assesment.

> Another example is the Internet gateway system I use.  It's a P3-800 and I 
> have no plans to upgrade it because it can handle higher speeds than my ADSL 
> link and that's all that is required.

Same as above: Its not like you are forced to use a P3-800 or a even
more over-sized system for that purpose. An atom might fit and will have
less power consumption.

> > Also to actually draw any conclusion from your statistics, one would
> > need to know more about the hardware in question. Especially its unclear
> > weither the PSUs used in the systems all have the same efficency.
> 
> Whether the PSUs are of the same efficiency doesn't matter much as the options 
> for switching them are limited.

No, the options for switching them are totally unrelated to a
comparison of the absolut power consumption.

> In the unlikely event that the P3 class
> desktop PCs I tested gave better results than Pentium-D and other newer 
> systems because of having better PSUs it wouldn't matter as the newer systems 
> need SATA connectors and an extra 4 pins on the motherboard connector.

The point is not weither you can change the PSU of a P3 with the PSU of
an Pentium-D or newer. The point is weither a Pentium D with a better
Pentium D-suitable PSU would have given different results.
(or same vice versa)
Because, today you can chose between PSUs which (usually) vary between 70%
and 90% efficiency. Dunno what efficiency previous PSUs had.
So if your P3 might happen to have a PSU with an efficiency of 90%,
while your Pentium-D has an efficiency of 70%, this *will* result in a
significant difference in comparibility of the two values.

> But I don't expect that PSUs have become less efficient, if anything I would 
> expect them to have improved slightly in recent times.  Maybe a P3 system 
> would use even less power if it had a PSU taken from a newer system such as a 
> Pentium-D.

Well, while that is your expectation, you did not back it with facts and
therefore we need to assume that this expectation is false.

-Patrick


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