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Do i7's have power saver if idle?

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September 15, 2009 9:16:08 PM

I've read some comments that. Example my i7 920 is idle. The processor will only use 1core @ 1.60ghz. Is this true?

More about : power saver idle

September 15, 2009 9:21:21 PM

No, all cores will remain active, but the "Intel Speedstep" function (if it's not disabled in the BIOS) will throttle clockspeeds and core voltages back when idle, effectively reducing power consumption, but even without speedstep any CPU consumes less power when idle.
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September 15, 2009 10:20:22 PM


thanks for the reply..
the i7 920 requires 130w. so does it mean.. it idles at 130w? or it will reduce?
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September 15, 2009 10:23:26 PM

ak47carbine said:
thanks for the reply..
the i7 920 requires 130w. so does it mean.. it idles at 130w? or it will reduce?


It will consume much less at idle.
It consumes 130W at full load at stock speed, full load means all cores 100% active, that won't happen with daily use or even gaming.
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September 15, 2009 10:47:34 PM

Gulli said:
No, all cores will remain active, but the "Intel Speedstep" function (if it's not disabled in the BIOS) will throttle clockspeeds and core voltages back when idle, effectively reducing power consumption, but even without speedstep any CPU consumes less power when idle.


The i7 has the capability to fully shut down idle cores, not just throttle them back. This is part of the reason the new i5 and 1156 i7 CPUs have such low idle power.
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September 15, 2009 10:58:37 PM

cjl said:
The i7 has the capability to fully shut down idle cores, not just throttle them back. This is part of the reason the new i5 and 1156 i7 CPUs have such low idle power.


Yes, but I don't think the 920 has that feature.
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September 15, 2009 11:06:48 PM

Ok, now it is clear to me. Thank you so much guys.
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September 16, 2009 1:28:14 AM

Gulli said:
Yes, but I don't think the 920 has that feature.

Every i7 has that feature. The socket 1366 models still take a lot of power at idle (comparable to older core 2 quads) because the northbridge and all the RAM takes a decent amount of power, but the newer ones really show the benefit.
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September 16, 2009 6:50:09 AM


in your instinct :D 
so how many watts at idle??
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September 16, 2009 4:09:02 PM

ak47carbine said:
in your instinct :D 
so how many watts at idle??


Maybe 30W to 50W, but that's just my gut feeling, could just as well be 15W, but when looking for a PSU you always have to keep a 100% loaded CPU in mind.
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September 16, 2009 4:11:23 PM

30W to 50W sounds about right.
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September 16, 2009 4:26:31 PM

At idle my cpu is only doing 10 watts at .918v and it's still set at stock, were do you get 30-50 watts at idle for a I7-920?
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September 16, 2009 4:31:35 PM

ak47carbine said:
in your instinct :D 
so how many watts at idle??
CPUID shows my Core i7 920 at a little under 50W at idle.
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September 16, 2009 5:56:21 PM

kg4icg said:
At idle my cpu is only doing 10 watts at .918v and it's still set at stock, were do you get 30-50 watts at idle for a I7-920?


Just curious. How do you get that figure?
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September 16, 2009 6:24:30 PM

sminlal said:
CPUID shows my Core i7 920 at a little under 50W at idle.

I'd bet the CPU alone uses quite a bit less than that. With the northbridge and memory, that could be about right though.
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September 16, 2009 6:27:48 PM

there is a utility for gigabyte boards called dynamic energy saver that shows wattage used by the cpu. it woks quite well.
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September 16, 2009 6:47:00 PM

But is it correct? I've yet to find a power utility like that that I would trust.
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September 16, 2009 7:53:45 PM

The Intel datasheet shows that the CPU itself consumes 12W of power in the C6 state - that's the lowest possible power level before entering sleep state with the processor clocks quiesced and the register contents flushed out to cache. So if you consider that to be "idle" then yeah, that's the official power consumption of the chip.

What I treat as "idle" is when the CPU is active and responding to user input, but with the cores at essentially zero percent utilization - and under that definition mine is consuming a tad less than 50W.
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September 16, 2009 8:11:22 PM

sminlal said:
The Intel datasheet shows that the CPU itself consumes 12W of power in the C6 state - that's the lowest possible power level before entering sleep state with the processor clocks quiesced and the register contents flushed out to cache. So if you consider that to be "idle" then yeah, that's the official power consumption of the chip.

What I treat as "idle" is when the CPU is active and responding to user input, but with the cores at essentially zero percent utilization - and under that definition mine is consuming a tad less than 50W.


I agree, and it also depends on the vcore that's being applied to the chip: "auto" settings doesn't necessarily mean "lowest vcore possible".
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September 16, 2009 9:15:56 PM

I see, i haven't overclock my i7 920 it is still @
2.66ghz.. So what is the suggested vcore? Thank you.
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September 16, 2009 9:22:45 PM

Well thats a good grief.. I thought the cpu idle power reaches 100w or something.. now the gpu, im worried about,.
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September 16, 2009 9:24:42 PM

ak47carbine said:
I see, i haven't overclock my i7 920 it is still @
2.66ghz.. So what is the suggested vcore? Thank you.


Depends, I've got 1.21875V for 3.2ghz, but every chip is different.
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September 16, 2009 9:44:08 PM

Every chip is different - if you don't plan on overclocking, leave it on auto though. If you do plan to overclock, the recommended maximum is either 1.375V or so, or 80C full load (some people will say a bit lower than this). You can overclock as far as you want until you hit one of these limits. In many cases with the i7, you'll hit the thermal limit first though.
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September 17, 2009 12:09:57 AM

ok thank you so much guyz.. i really appreciate all your help.. one last question..up to now i havent applied some thermal paste in my cpu.. but the stock hsf had some pre applied thermal paste. is it ok?? im not planning to overclock my i7 920 ..
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September 17, 2009 12:14:21 AM

It should be fine, yes.
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September 17, 2009 12:38:54 AM

sminlal said:
CPUID shows my Core i7 920 at a little under 50W at idle.

The problem is that by using software that is polling for power consumption data you are possibly preventing some cores from entering the deeper C-states. Kind of the same reason (among many others) why you can't measure idle temperatures that accurately either, because you're polling every core in that case.
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September 23, 2009 5:10:16 PM

Here is a wattage measurement from Everest for the cpu at idle



and by the way I was gpu folding at the time I took this screen shot
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