Windows Vista and CPU low power mode

[coldfire]

Hardware: X61T, L7500, 4GB RAM
OS: Windows Vista Business (all updates applied)
When I set CPU to "Low" or "Lowest" in Lenovo Power Manager, the CPU still runs at highest frequency (1.6GHz, using CPU-z to monitor).
While another laptop, x60s with L2400 and running Windows XP, when set to "Low" in power manager, will run at half of maximum frequency.
Anyone know the reasons?
Thanks,

[coldfire]

When I set the CPU to "Adaptive" mode, I can see the operating frequency switches between 1.6GHz (x8 ) and 1.2GHz (x6). Any other modes (High, Low, Lowest) always make CPU operate at max frequency.

[awolfe63]

I think that the settings are separate for AC and battery. AC may be full frequency even on low. You can set min and max percentages in the Vista power control panel for each - but that may interfere with the Thinkvantage stuff.

[coldfire]

thanks for the reply.
I tried both with AC and battery, results are always similar.

[coldfire]

update:
It seems that CPU-z does not report correctly, today I tried vista's own resource monitor and RMClock, they both report that CPU is working in the proper mode.

[awolfe63]

Ah - yes. I had a similar problem. MOBmeter seems to do OK in certain modes. The best choice, however, is the Intel thermal analysis tool (google it - I can't find it on the Intel site right now but it seems to be on third party sites.)