CPU scaling nonexistent with Inspiron 5150

James Wilkinson ubuntu at westexe.demon.co.uk
Fri Jun 3 12:38:19 UTC 2005

Samuel Kaufman wrote:
> When powernowd starts, I get the following...
> emrys at cloudy:/sys/devices/system/cpu$ sudo /etc/init.d/powernowd start
> Password:
> This processor "Mobile Intel(R) Pentium(R) 4 CPU 3.20GHz" is known
> _not_ to support power-saving.
>   * Starting powernowd...
>   * CPU frequency scaling not supported                                   [ ok ]
> That's not good. CPU scaling should be supported. According to
> http://www.finnie.org/linux-dell-5150/, it's supported with the 2.4
> kernel in Gentoo. (Though he doesn't specify which Gentoo kernel he
> uses.)

CPU scaling needs to be supported both in hardware and in software. Not
all CPUs can scale -- ever, under any OS.

CPU scaling is supported in software, and it seems to work very well on
my (desktop) Athlon 64 3200+. The error message you get says that your
*hardware* won't do power saving.

Incidentally, your processor is not an ideal laptop processor. It's
*very* power hungry, needs a big heatsink, and should only be used in
"desktop replacement" luggable laptops: ones that aren't sold as being
very portable, nor good at remaining away from a power socket for a long
time. On the other hand, you should have got a lot of CPU power for the
price: the alternative would have been a fast Pentium M which I imagine
would have been considerably more expensive.

Buying laptops is a trade-off: not just performance and price, like on a
desktop, but weight, portability, screen size, and battery life. I'm
afraid it sounds as though you've got one that *isn't* particularly good
for intercontinental flights.



E-mail address: james | Beneath this stone lies Murphy,
@westexe.demon.co.uk  | They buried him today,
                      | He lived the life of Riley,
                      | While Riley was away.

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