Speedstep values for IA32_PERF_CTL, E6750

[_void_]

I'm trying to find the tail end mv (millivolt) values for the IA32_PERF_CTL register on a E6750 Core 2 Duo. I realize that bits 15:8 represent the coremultiplier and that bits 7:0 represent the core mv value, but don't know how to calulate the required core voltages when the frequency gets stepped down. At max value the nominal voltage is 1.35V which comes out to a value of 0x0828, but what are the requiredvotlages for lower p-states? Also I was curious as to how many p-states are available? I know that there are8X and a 6X levels but is there a 7X level or anything below 6X (I've read that 6X is supposed to be the minimal multiplier for most intel processors p-states).

[Intel_Software_Netw1]

Our engineering team responded that most of these details are in the BIOS Writers' Guide, are processor/platform specific, and are not publicly documented.

For the second part of your question, 6 is the minimum supported multiplier for Core2 Duo. The platform BIOS vendors pick the frequency voltage based on the platform's specifications (and following the guidelines in our BIOS writers guide), and the user/OS should use the multipliers and voltage levels exported by BIOS through ACPI methods.

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Lexi S.

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