No SpeedStep / CPU scaling in XP on new Alu Macbook

Question

Installed XP Home SP2 via Bootcamp on my Late 2008 Macbook (2.0 ghz)
Was surprised to see the battery life go down by half under XP compared to Leopard
A quick check revealed that the CPU is running at full throttle (1.99 ghz even with 0% CPU utilization)
Why should this be the case.
I have the power options set to max battery and the CPU should be scaling itself down to lower clocks when not loaded
Can someone else with a late 08 MB also please check this and let me know

Answer 1

Hi Hatter, further to our other thread, the fundamental problem here is that Apple hardware uses EFI, not BIOS. There are many Windows apps for controlling CPU and GPU fan speeds, but they all rely on genuine BIOS hooks to control the physical hardware. Boot Camp provides a pseudo BIOS layer (over EFI) to allow install of Windows, but it does not go the extent of supporting CPU fan control, so Windows users are dependent on waiting for Apple to provide CPU fan control functionality in Boot Camp.
With regard to the NVidia 9400M GPU in particular, this is the only GPU/chipset range that NVidia does not provide consumer support for in their recent public driver release. Since Apple is the OEM that designed the implementation of 9400M on the Apple notebooks, only Apple can create drivers for them. So again, Windows users are dependent on waiting for Apple to provide GPU fan control funcionality in their Windows graphics driver under Boot Camp.
Message was edited by: peterjmacbook