Core 2 MSR register documentation

Core 2 MSR register documentation

I spent the whole day looking on intel's webpage and I didn't find the documents that describe the MSR registers (and fields) in intel core 2 processors. I am specially interested in Penryn model.

I need to know about the IA32_MSR_PERF_STATUS and how to translate the vid values into real voltages.

Where can I find that information?
Thank you for your time :)

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For more complete information about compiler optimizations, see our Optimization Notice.

MSR information can be found in Appendix B of the processor manual set at

VID information can found in the data sheet of specific processors. A word of caution, the VID interface can change with processor stepping, they are also different across product segment. Therefore they were defined with BIOS in mind as the intended usage.

You are wrong twice.

1. "MSR information can be found in Appendix B" - there are no VID information

2. "VID information can found in the data sheet of specific processors" - there are no any datasheet for Intel Core 2 Duo T8300.

Is it a secret information?


Shihjong is right, only think he forgot to mention the spec name. MSRs are defined in appendix B.1 of 3B.

Another thing the name of the MSR is IA32_PERF_STATUS

VID information can be found after selecting the processor and the corresponding document. Here is another document with VID values for multiple processors:

I alreay read 253669 as well as 253668. There are no VID information forIA32_PERF_STATUS=0x198

Appendix B1, table B-2, page 650, table B-3 page 687

About 322172.pdf

T8300 didn't found

MSR didn't found

IA32_PERF didn't found

Yes, I found VID-Voltage table for T7500 but I still has no information about VID inIA32_PERF_STATUS

I thought you have two questions:

1. One was documentation regarding MSR as I said us explained in 253669 apendix B.

2. Second was documentation for VID.

VID documentaion is in datasheet for each processor. Please check this document for 7000-8500 desktop series (E8500):

For Mobile parts:

It looks like you are trying to do speed stepping. There are a few whitepapers on this subject on Intel website. One is for Linux OS:

if you dont find it, just google speed step intel .... there is plenty of information.

I see somemisunderstanding

There is no any VID information in the bit fields.

I also read 31674505. There is no T8300 processor. OK, I can suppose that it is the same as T7700. Is it true?

Thank you for the link on Linux article while there ia no such information.

I understand that you do not want to open this information

The current
operating point can be read from IA32_PERF_STATUS. IA32_PERF_STATUS is
updated dynamically.
The 16-bit encoding that defines valid operating points is model-specific. Applications
and performance tools are not expected to use either IA32_PERF_CTL or
IA32_PERF_STATUS and should treat both as reserved.

Nope, there was a datasheet published on Intel's web site that documented the processor in question but it seems to be no longer be on the web site. Intel, can you find the datasheet for the mobile Core 2 processors on the 45nm process for platforms based on mobile Intel 965 series chipsets and add the link or publish it again?

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