QPI and Uncore Clock question (OCing i7-920)

[jedinegotiator]

Ok so I am going to overclock my intel i7 920 by upping the base clock. By doing this I need to step down the QPI, Uncore, and Memory multipliers.

 

I got the memory multiplier down but I have a few questions. How do I know how high I can set the QPI clock to? How do I know how high I can set the Uncore clock to? Also is it ok to go a little over the RAM clock? I have 1333 DDR3 ram...will it be ok to sett it a little higher than 1333 or not?

 

Here is a calculator I am using see if it looks good on he overclocking settings I have:

 

 

This gets my CPU to 3.8 Ghz...how do I know if the QPI clock is too high or the Uncore? The RAM clock should be find as it is just under 1333.

 

Also will I have much extra heat with this overclock sense there is no extra voltage involved?

[ir_cow]

i would look at other posts on the forums they cover you questions in dept. i7 920 OC. in short ever cpu is different but we all strive for 4ghz, 200BLCK, 3400QPI, 2600 UNCORE. i mean your dead close to 4ghz and you'll know when the settings are to high because it won't post.

 

i actually don't remember what the QPI muti should be. i think min 13x but im not sure.

Edited April 4, 2011 by hornybluecow

[wevsspot]

Jedi -

 

Don't over complicate this. Any decent motherboard with the most recent BIOS update will adjust your qpi frequency and your uncore frequency just fine if left on the "Auto" setting.

 

Now, if you want to get down to the nuts and bolts of it............. your QPI speed is determined by;

 

bclk x qpi multiplier = qpi clock speed

 

a fairly common and simple example

 

blck = 133 x qpi multi 18 = 2394Mhz (2400Mhz rounded and otherwise 4.8GT/s)

 

There are three standard qpi frequency multipliers which give you 4.8GT/s, 5.6GT/s and 6.4GT/s at a 133 bclk depending on the QPI multiplier.

 

Most quality motherboards will let you run QPI in the neighborhood of 7.2GT/s with the proper tweaking. However, in my experience most socket 1366 boards will let you run an effective QPI anywhere between 6.0GT/s and 7.0GT/s without much issue.

 

In your example above your qpi clock is 3420Mhz (otherwise 6.84GT/s). So you should be fine.........................

Edited April 4, 2011 by wevsspot

[MercuryDoun]

Jedi -

 

Don't over complicate this. Any decent motherboard will adjust your qpi frequency and your uncore frequency just fine if left on the "Auto" setting.

 

 

QPI should be fine at less than 8000 MT/s... Why arent you using the x21 Multi? The 920 is capable of using it. 191x21 = 4Ghz!!! This will result in your not needing to change anymore of your QPI/Uncore settings.

[jedinegotiator]

Its base clock is x20...x21 is if turbo boost is turned on which it is now but I heard somewhere that when overclocking the turbo boost feature should be turned off.

[El_Capitan]

Its base clock is x20...x21 is if turbo boost is turned on which it is now but I heard somewhere that when overclocking the turbo boost feature should be turned off.

[jedinegotiator]

D=

[wevsspot]

On some boards (many Asus boards for example) once you turn on the Turbo feature even one time, you can turn it off and the x21 multi will still be available

[jedinegotiator]

So instead of only sometimes using a X21 multiplier it will always use it?

[wevsspot]

If you manually set the CPU multiplier to 21 instead of using the Auto setting........... Yes

[IVIYTH0S]

Yeah I was worried the 21x multi would only work for 1 of my cores but I've confirmed it's working for all 4

[MercuryDoun]

On some boards (many Asus boards for example) once you turn on the Turbo feature even one time, you can turn it off and the x21 multi will still be available

 

Exactly!

 

 

So instead of only sometimes using a X21 multiplier it will always use it?

 

Yup, just set it manuall to use the x21 Multi and your good to go!

 

Yeah I was worried the 21x multi would only work for 1 of my cores but I've confirmed it's working for all 4

 

Thanks for confirming! And hopefully this helps you as well!