i5/i7 Lynnfield QPI/VTT voltage

[mrsparkle1811]

They must have re-evaluated them as part of Xeon 1156.

 

[konakona]

Sorry if this has already been posted but Intel have adjusted the specifications this month. Refer to the datasheet in the first post.

Vcc Absolute Max is now 1.4
Vtt Absolute Max is now 1.4
Vddq Absolute Max is 1.8

Nice to know we can now push higher overclocks while still remaining within absolute maximum spec.

That really helps. Let's see if I can push my 860 past 3.7ghz

 

[MadScientist]

Thanks mrsparkle1811. Nice find.
Thanks Intel. Now I go back and tweak a few more voltages to try to squeeze a bit more out of my i5-750.

 

[ehume]

Mr. Sparkle - do you have a link to the original from Intel?

 

[NumericalMethods]

It's here

http://ark.intel.com/Default.aspx

You just need to look up your specific processor and the voltage table is on data sheet 1.

Ooo! I've been waiting to update my mobo BIOS and re-clock my rock solid system for some time. This could be the decider for me

 

[ehume]

Yup. For the i7 860 it's all in table 7-4, here.

 

[konakona]

yoohoo, now I am doing 4ghz completely stable. Probably could push it a bit further but I am pretty happy with what I got now

 

[RussianSensation]

How come Table 7-6 still shows Voltage for the memory controller and shared cache defined at the socket motherboard VTT pinfield at 1.155V? I tried bumping my Vtt from 1.25 to 1.41, but then I need VCore of 1.376 from 1.312V to get from 3.9ghz to 4.0ghz. Temperatures increase by 8*C for 100mhz speed boost (+2.5&#37. It's just NOT worth it at all.

If anyone is interested, power consumption on Core i7 860 approaches ridiculous levels past 3.6ghz (i.e., once you increase your Vcore past 1.30V): http://www.xbitlabs.com/articles/cpu/display/power-consumption-overclocking_10.html#sect0

By the way, beyond 4.0ghz, overclocking a Core i7 is just 'laughable' on air cooling unless one is chasing records. Core i7 950 consumes another 52W of power from 4.0ghz to 4.2ghz...http://www.xbitlabs.com/articles/cpu/display/power-consumption-overclocking_11.html

 

[konakona]

heh you are right, for what I do (just gaming) it offers no tangible benefit at all.
does make be feel better about the computer, but oh well

 

[Kenmitch]

How come Table 7-6 still shows Voltage for the memory controller and shared cache defined at the socket motherboard VTT pinfield at 1.155V? I tried bumping my Vtt from 1.25 to 1.41, but then I need VCore of 1.376 from 1.312V to get from 3.9ghz to 4.0ghz. Temperatures increase by 8*C for 100mhz speed boost (+2.5&#37. It's just NOT worth it at all.

Hmmm....The cpu vtt bump needed to make the 100mhz jump doesn't seem logical to me. Maybe some other voltages or bios setting would need tweaked or maybe your chip is throwing in the towel

Does your MB have frequency adjustment options available?

My eVga has the following available.
CPU PWM Frequency :
VTT PWM Frequency:
DDR PWN Frequency:

For my i5 750 I needed to play with the cpu pwm to make the jump from 4ghz to 4.2ghz and need the cpu vtt at 1.28v for stability.

 

[ehume]

IIRC table 7-6 shows the recommended top end. Above that, Intel says your cpu might not work well at lower voltages when you try to go back down. What is different now is the absolute max voltage. For Vtt, that used to be 1.21v, IIRC. That's why I always kept mine at 1.19v.

 

[ekoostik]

Those are not insignificant revisions upward. Has anyone seen any explanation why Intel raised these absolute maxes? Is this something they have a history of doing?

 

[ehume]

More importantly: can we trust it? Or is it a typo? Here is where ekoosik's question is important. If we know the history we can have confidence in the new number.

 

[Kenmitch]

More importantly: can we trust it? Or is it a typo? Here is where ekoosik's question is important. If we know the history we can have confidence in the new number.

I agree. I was kinda wondering why the absolute max vcore went from a blistering 1.55v down to 1.40v at the same time. But on the other hand I'd rather have more cpu vtt to play with

 

[BababooeyHTJ]

I'm not sure how much anyone cares anymore but has anyone checked Table 7-4 recently? It now says that the absolute max VTT is 1.4v. I wonder when that changed.

 

[ekoostik]

I'm not sure how much anyone cares anymore but has anyone checked Table 7-4 recently? It now says that the absolute max VTT is 1.4v. I wonder when that changed.

About a year ago. See the post in this thread from 6/24/2010