Turbo Boost and Speed Step Question

[Aptos]

Hey guys,

New here and new to OC'ing, so sorry if the answer is somewhere else in these forums; I searched around and couldn't find the answer.

I just OC'd my i7-920 and got it stable with:
base clock: 167 MHz
cpu vcore: 1.2v
LLC: On (level 2)
C1E (enhanced halt): off
C2/C6/C7 state support: off
cpu mult: 20
uncore mult: 16
QPI mult: 18
mem mult: 8

I use the Corsair H50 and after a 24 hour prime95 blend torture test the max T junction temp ended at 63* C on one core but the others all had a 59* C max.

Anyway, I have two questions.

1) When I enable Turbo Boost, my cpu multiplier seems locked at 21. Even when running another prime95 blend for 2 hours it stayed at 21. Is that the intended purpose of Turbo Boost; to just add 1 to your multiplier constantly?

2) When I enable EIST (Intel's speed step), my multiplier never reduces and my core voltage stays at 1.18v and rises to 1.2v under load. This is exactly what my core voltage was doing before I enabled EIST (Actually, I was seeing a voltage droop under load, so I enabled LLC for that voltage increase under load; up to what I set the vcore to in the BIOS). Is this out of the ordinary?

 

[KILLER_K]

1) http://www.maximumpc.com/article/features/everything_you_need_know_about_nehalems_turbo_mode

2) You need to enable:
* Intel Speed Step { Operating system controls the speed.}
* CPU ™ {Throttles back to reduce heat.}
* C1E {allows Halt State Support.}

 

[Aptos]

1) http://www.maximumpc.com/article/features/everything_you_need_know_about_nehalems_turbo_mode

2) You need to enable:
* Intel Speed Step { Operating system controls the speed.}
* CPU ™ {Throttles back to reduce heat.}
* C1E {allows Halt State Support.}

Thanks for the info. Enabling C1E allowed for the dynamic cpu multiplier. Although the voltage isn't doing anything different.

Another interesting note is that CPU-Z 1.53.1 doesn't show my multiplier dynamically changing, but Real Temp 3.40 does.

One more question: how beneficial is this dynamic multiplier? I don't see any difference in core temps at idle.

 

[Zero82z]

One more question: how beneficial is this dynamic multiplier? I don't see any difference in core temps at idle.

It's meant for power savings, not temperature reduction. Although the fact is that the CPU is already consuming so little power at idle that you're not likely to notice much of a difference.

 

[prasvt]

So wait - what if you want the multi to stay locked at 21? What combo of settings should be set?

 

[KILLER_K]

You disable what i put in there and it locks it at 21 multi. But i rather mine go down when not in use as i see no need to idle at 4.0GHz or better.

You need to disable:
* Intel Speed Step { Operating system controls the speed.}
* CPU ™ {Throttles back to reduce heat.}
* C1E {allows Halt State Support.}

 

[nzaneb]

So wait - what if you want the multi to stay locked at 21? What combo of settings should be set?

Only certain motherboards will allow you to lock your multiplier at 21. EVGA, for example, does not allow it. Enabling Turbo is the only way to utilize the 21 multiplier.

@ OP. Putting any sort of stress on the CPU will make turbo kick in and you will see the 21 multiplier.

 

[Aptos]

@ OP. Putting any sort of stress on the CPU will make turbo kick in and you will see the 21 multiplier.

I was able to lock my multiplier at 21 by enabling turbo boost but disabling C1E, C3/C6/C7, and EIST.

Does anyone have an opinion on whether a 3.5 GHz OC with a 1.2v core should have those power saving settings (C1E, C3/C6/C7, EIST) enabled?