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Disabling c3/c6 on P8Z68-V/Gen3 to fix whining noise

Last response: in Systems
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December 21, 2012 8:05:24 PM

Hi,

My motherboard is emitting a high pitched whine, as discussed here: http://www.tomshardware.com/forum/300515-30-p8z68-high-pitched-noise-coming-motherboard.

Up until now, I have been using this solution:

jesdanco said:
Could be power management issue - try this - works a treat

1. Execute: "regedit"
2 .Locate: HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ Power \ PowerSettings \ 54533251-82be-4824-96c1-47b60b¬740d00 \ 5d76a2ca-e8c0-402f-a133-215849¬2d58ad
3. Change Attributes from 1 to 0.
4. Then, through the control panel - power - in the settings mode select power management processor. There will be an option disabling idle processor and high pitched noise immediately disappears.


However, in the thread I linked, people discuss disabling the c3/c6 power states. Are these two solutions the same, other than one being at the BIOS level and the other being in Windows?

If they are the same, is there any downside (to overclocking especially) to disabling c3/c6 apart from some wasted electricity? Also how much would be wasted? Enough to impact my electric bill in any way?

Thanks.
a b B Homebuilt system
December 21, 2012 10:46:32 PM

Sleep (C3), cuts all internal clock signals from the CPU, including the clocks from the bus interface unit and from the APIC. This means that when the CPU is in the Sleep mode it can’t answer to important requests coming from the CPU external bus nor interruptions.

(C6) When the CPU enters this state it saves its entire architectural state inside a special static RAM, which is fed from an independent power source. This allows the CPU internal voltage to be lowered to any value, including 0 V, what would completely turn off the CPU when it is idle. Then when the CPU is waked up it loads the previous state of all internal units from its special static RAM. Of course waking up the CPU from this state takes a lot longer than the previous states, but it is faster than turning off the computer and then turning it back on and loading the operating system

C0 – Active: CPU is on. C0 is the operating state.
C1 – Auto Halt: core clock is off. C1 is a state where the processor is not executing instructions, but can return to an executing state essentially instantaneously. Some processors also support an Enhanced C1 state (C1E) for lower power consumption.
C2 – Stop Clock: core and bus clocks are off. C2 is a state where the processor maintains all software-visible state, but may take longer to wake up.
C3 – Deep Sleep: clock generator is off. C3 is a state where the processor does not need to keep its cache coherent, but maintains other states. Some processors have variations on the C3 state (Deep Sleep, Deeper Sleep, etc.) that differ in how long it takes to wake the processor.
C4 – Deeper Sleep: reduced VCC
DC4 – Deeper C4 Sleep: further reduced VCC

This is all you will be loosing if you turn them off. All mine are off and I don't have any problems. Does that answer your question?
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December 21, 2012 11:32:14 PM

Thanks for those resources. I've actually read a lot of that and was hoping for a more basic explanation. Basically I'm wondering if disabling c3 and c6 will increase my power consumption enough to make a difference on my electric bill, and if these features have any impact on overclocking as I know some of them can mess with voltage.
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Best solution

a b B Homebuilt system
December 21, 2012 11:43:18 PM

Yes, they will cause a slight increase in the power consumption of your system. It will make a difference in your power bill, but it will be less than pennies a month. Just opening the refrigerator door a time or two will cost you more.
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December 28, 2012 11:25:14 PM

Best answer selected by fireketchup.
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