Software Tuning, Performance Optimization & Platform Monitoring
Discussion regarding monitoring and software tuning methodologies, Performance Monitoring Unit (PMU) of Intel microprocessors, and platform updating.
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MSR 0x1AD (Turbo Ratio Limits)

I know that I have read about it in one of the datasheets, but I cannot for the life of me find it anymore.
What I am looking for is that document, like 326019.pdf and others, which talks about it, when two cores are active.
Usually this MSR is used when only one core is active, but maybe it was for the X79 or the new Z77 PCH that now support two cores at once. I forgot. And that is where you experts come in handy ;)
Also. When will 200 MHz banks be used? Wasn't that also for the Ivy Bridge CPU's?
P.s. I hope that I am not breaking any rules (NDA) but I really need this info a.s.a.p. Please contact me per e-mail when I did.
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MSR 0x1ad is documented in the SoftwareDevelopment Manualvol 3, chapter 34.
Search for '1adh'.
The main website for the SDM is

The Vol 3 manual is available at
Thanks for the links. I have all documents, be it in split up in form (3A, 3B and 3C). The combined one is much more fun to use so thanks again.Problem is however not resolved. The documentation states: "Maximum turbo ratio limit of N core active."And like I said. I have seen an Intel document explaining the new speedstep where 2 simultaneous cpu-cores are active, per ratio (shareing the same bits). Bank feature was also changed to support 200 MHz.I though to go read it at a later time. Was busy with something else (writing a test report for the 3770K) and I wish I had made a note about it. But I didn't. Stupidly. Now I need it and can't locate it anymore, but trust me. It is there ;)

Update: I found the reference to the 200 MHz but that was for RAM. Not the CPU. Oops.