Super LFM question

[jespada]

Hi All,

Does anyone know why Super LFM is not enabled for Macbook 13" Aluminum late 2008 model?

I just found this out after I installed Bootcamp and Windows 7 on my Macbook 13" with P8600 2.4Ghz CPU 2GB RAM and 250G HDD after more than a year of using it.
After I installed the CPU monitoring widget on Windows 7 and CPUZ, I noticed that the lowest Freq that my Macbook operates even with <5% CPU load is only 1.5Ghz and VID @1.0V.
I installed Coolbook on OSX to confirm what I saw on Windows. I was surprised that SLFM is not visible in Coolbook which is the same result I got from Windows 7 CPU monitoring widget and CPUZ.

I checked with our local Mac support and they got the same results for all of Macbook 13" Aluminums late 2008 model. SLFM is not visible on Coolbook which means, it is not enabled.

I tried to install Coolbook on my wife's Macbook Pro 13" 2010, which has the same spec, P8600 2.4Ghz CPU and 250G HDD. The only difference is the memory which is 4GB RAM. There, SLFM is enabled and works just fine, running at 798Mhz @0.875V.

Below is what I got from Coolbook for comparison. As you can see the late 2008 Macbook has no SLFM info.

Legend:

SLFM - Super Low Freq Mode
LFM - Low Freq Mode
HFM GV - High Freq Mode (Geyserville/Speedstep)
HFM - High Freq Mode

Macbook 13" Aluminum (Late 2008) P8600 2.4Ghz 2GB RAM 250GB HDD

Freq VID
SLFM -- --
LFM 1596Mhz 1.0000V
HFM GV2 1862Mhz 1.0500V
HFM GV1 2128Mhz 1.1000V
HFM 2394Mhz 1.1375V

Macbook Pro 13" Aluminum (2010) P8600 2.4Ghz 4GB RAM 250GB HDD

Freq VID
SLFM 798Mhz 0.8750V
LFM 1596Mhz 1.0000V
HFM GV2 1862Mhz 1.0500V
HFM GV1 2128Mhz 1.1000V
HFM 2394Mhz 1.1375V

Can anyone please help confirm if this is really the case for Macbook 13" late 2008 model?
Because I checked the Intel P8600 Datasheet and SLFM should always be enabled. Otherwise, it will affect the battery life as well as long term reliability of the CPU.

I tried to raise this issue in several Mac forums but did not get any answer. So i'm trying my luck here in CPU Forum.

Thanks in advance for your help.