Re: Power consumption HZ100, HZ250, HZ1000: new numbers

Ondrej Zary
2005-08-02T16:11:57Z

James Bruce wrote:
> Stephen Clark wrote:
>
>> Maybe new desktop systems - but what about the tens of millions of old
>> systems that don't.
>
>
> If it's an old system, it probably doesn't have working ACPI C-states
> though. Without that, low HZ does not save you anything. I should have
> said: 99% of desktops with the capability to do ACPI sleep have at least
> one USB device attached (usually a mouse).

rainbow@pentium:~$ cat /proc/acpi/processor/CPU0/power
active state: C2
max_cstate: C8
bus master activity: 00000000
states:
C1: type[C1] promotion[C2] demotion[--]
latency[000] usage[00052470]
*C2: type[C2] promotion[--] demotion[C1]
latency[090] usage[02699149]

This is PCPartner TXB820DS motherboard (Socket 7, i430TX) with 1998
Award BIOS and C-states seem to work fine. I've tested it in Windows 98
some time ago - the CPU is almost cold when idle with ACPI enabled and
hot with ACPI disabled (that's partly caused by the fact that Windows 9x
does not HLT the CPU when idle). With Pentium 100MHz in the socket and
ACPI enabled, I could even touch the CPU (without heatsink) without
burning my fingers.

--
Ondrej Zary