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Power consumption HZ100, HZ250, HZ1000: new numbers

From:  Marc Ballarin <>
Subject:  Power consumption HZ100, HZ250, HZ1000: new numbers
Date:  Sat, 30 Jul 2005 00:49:24 +0200
Archive-link:  Article, Thread

I was finally able to get C3 state working. It seems that my BIOS is
leaving USB controllers in an active state(?). Without any USB drivers
loaded, C3 is not possible. With drivers loaded, but no device plugged
in C3 works fine. Kernel is 2.6.13-rc3-mm3 + acpi-sbs.

With working C3 there are indeed differences:

Voltage is 16.5 V

HZ=100:  ~460 mA => 7.59 W
HZ=250:  ~468 mA => 7.72 W
HZ=1000: ~494 mA => 8.15 W

Results are quite stable.

Test environment:
- Pentium M 1.60GHz, model 13, stepping 6
- ondemand governor with acpi-cpufreq (idle at 600MHz)
- no daemons running
- no external devices attached, except display
- WLAN disabled via kill switch
- internal display disabled
- hard disk in sleep mode (hdparm -Y), data dumped to ramfs
- kernel configuration attached


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