have to admit I've not tried fractions of mutil's yet I just know they are supported on my system.
can you enter fractions into BIOS?
But of course! And the ratio can be anything from 6 to 9 on my Asus P5K PRO. I personally use a CPU ratio of 7.5 with a FSB speed of 400 (3GHz) so I have
to figure out what to use (how to calculate) since the Intel documentation is anything but helpful (requires NDA). I can't be the only one having this problem, and in fact I got four PM's �€“ this week alone �€“ from other P5K PRO users asking for my help.
And here's a first update:
I booted into Ubuntu Linux and ran dmesg | grep ACPI
which returned this (the most important bits only):
ACPI: SSDT CFF8E0D0, 01D2 (r1 AMI CPU1PM 1 INTL 20060113)
ACPI: SSDT CFF8E2B0, 0143 (r1 AMI CPU2PM 1 INTL 20060113)
ACPI: SSDT CFF8E400, 0143 (r1 AMI CPU3PM 1 INTL 20060113)
ACPI: SSDT CFF8E550, 0143 (r1 AMI CPU4PM 1 INTL 20060113)
Then I used acpidump like this:
acpidump -a 0xCFF8E0D0 -l 0x01D2 > cpu1pm
acpidump -a 0xCFF8E2B0 -l 0x0143 > cpu2pm
acpidump -a 0xCFF8E400 -l 0x0143 > cpu3pm
acpidump -a 0xCFF8E550 -l 0x0143 > cpu4pm
Then I decompiled the files with:
iasl -d cpu1pm
iasl -d cpu2pm
iasl -d cpu3pm
iasl -d cpu4pm
Giving me four files (see attachment) named cpuNpm.dsl – where N is a number from 1 to 4. Which is great, but there is no _CST in the ACPI 2.0 Object Table:
_PCT Identifies location of I/O mapped MSRs for status and control
_PSS Lists the possible processor frequency and voltage operating states
_PPC Reflects the capabilities of the platform
And I have two different sets (SPSS and NPSS) in _PSS (see CPUxPM.zip) which I think can be of later use, if I only knew which one to use. There's also Method (_PSD, 0, NotSerialized) which I am still looking into; to see what it does.Update:
I found _PDC (Processor Driver Capabilities) on page 280 of ACPIspec30a.pdf
– deprecated in ACPI 3.0 in favor of _OSC.
Then I tried to run CPU-I, which unfortunately failed to work (startup errors) and thus I recompiled both the kext and the application for Snow Leopard. It starts but doesn't show any P-State changes, making me wonder why not as it is already part of my BIOS. OS X needs C-States the get P-States working?Update:
We 'only' need a _CST() object to get the temperatures down, but the temperatures go sky high without _PDC so you should not remove it!