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I have Dell Latitude E6420 with SandyBridge i5-2520M and standard issue Dell BIOS (version A15). In certain situations computer produces annoying high-pitched noise (it is not loud but it is noticeable). I know this issue is related to CPU entering certain power-saving modes (C-states). On my previous computer (Latitude E6410) it was possible to prevent CPU from entering deeper C-states (using ThrottleStop utility). Unfortunately, this is not possible with my current notebook as the feature is locked, probably in BIOS. MSR registry governing C-States (MSR_PKG_CST_CONFIG_CONTROL) cannot be altered and I am getting "General Protection Fault" when trying to do so.

  1. Is it possible to use UEFI instead of BIOS to make currently locked CPU features acessible?
  2. How are UEFI and BIOS related to each other?In computer architecture stack is UEFI over the BIOS (so the limitations set by BIOS are obligatoty for UEFI) or beside BIOS (UEFI is not limited by BIOS)?
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Question 2, possible… – Moab Nov 2 '12 at 0:08
Did you call Dell warranty support to report the issue? – Moab Nov 2 '12 at 1:01
Thanks for duplicity warning, corrected. I found Dell warranty support feedback from previous interaction with another user reporting the same problem:… (I did my googling homework before asking). Unfortunately, this is the flaw of previous Core-i CPUs I hoped SandyBridge would resolve. – JohnyCash Nov 2 '12 at 7:01
Unfortunately the workaround suggested by Dell is not an option for me as my ntb lacks bluetooth module. – JohnyCash Nov 2 '12 at 7:09

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