I7 920 OC, to Turbo or not to Turbo

warezme

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Dec 18, 2006
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I have my Turbo mode disabled in the bios. From what I gather Turbo mode pushes your computer CPU to auto OC one core and changes voltage settings as well. On high OC over 4Ghz the Turbo mode tends to push the CPU even higher and makes the system unstable over 4.2Ghz. I have disabled turbo mode but does Turbo mode have some sort of energy saving feature to the cores not being used?.

I never noticed any drop in temps when Turbo mode was on as opposed to it being off with any of the cores.

Bottom line is there any benefit to turbo mode if you already have a stable high OC machine. I noticed the extreme OC competition teams tended to disable it.
 

yobigd20

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Oct 24, 2008
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Personnally, I disabled speedstep/turbo mode and c1e, and left hyper threading enabled.

Turbo mode turns off unused cores and pushes more power to the other cores for its auto-overclocking. They switch cores automatically to control heat issues too.

I have my 920 running stable at 4.0ghz. I've had it stable at 4.2ghz too, but I fear killing my cpu so I just leave it at 4.0ghz.

To reach that and be stable, I had to set the following bios settings in my rampage 2 extreme bios:

Speedstep/turbo: disabled
c1e: disabled
BCLK Freq: 200
DRAM Freq: DDR3-1603Mhz
UCLK: 3208
CPU Differential Amplitude: 800mV
CPU Voltage: 1.43125
CPU PLL Volt: 1.94842
QPI/DRAM Core Volt: 1.375
DRAM Bus Volt: 1.65681
and I set my DRAM Timings to 8/8/8/24, which I'm running Corsair DDR3 Dominators that are specced at 1600Mhz.

I am watercooling my machine too. I have a 360mm Feser XChanger, Apogee GTZ CPU block with Arctic MX2 thermal paste, and swiftech MCP655 pump and using distilled water with some antifreeze in it.

My cpu temps never go above 55C when I push them very hard. I could probably overclock stable past 4.2ghz but I don't see the point of risking my cpu. Its fast enough already :)
 

warezme

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Your voltages look good and so do temps. Mine is air cooled as I did not want water cooling since my last machine was water cooled and was very difficult to manage when trying to move around. Mine is running super stable at 4.0Ghz and like you will also run fine at 4.2Ghz but I notice it occasionally blue screens when rendering a long Max scene or a couple of hours of gaming so I leave it at 4.0 Ghz most of the time also.

With turbo on it would auto push it up to 4.2Ghz and if I set to 4.2Ghz it would push it to 4.4, or 4.5 and blue screen out after awhile.

I have all thermal and speed step settings disabled and use the Corsair DDR3 6GB kit. Mine idles at 45 - 49 across all cores and will run 59 - 65 under full load. I have the same voltage set as yours.

The i7 920 is a very good chip, to much competition for the extreme version in my opinion. I don't see how they will sell very many of those. So far I see no reason to turn Turbo on.
 

wonton04

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Jan 1, 2009
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Well Im kind of a virgin to OCing anything, and would like some help OCing my Core i7 920 with the stock cooler. Doesnt have to be up to 4Ghz but Id like to get my hands wet for once.

I just have the Corsair Cosmos case and stock fan/paste for now. Any help would be great =)
 

seijirou

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If that's just a Cosmos case and not a Cosmos S, I would not suggest overclocking.

That case doesn't flow much air, you will probably have heat issues.

Unless, of course, you've done something to change this. I'm assuming you havn't as you mention you're using the stock i7 heatsink.