# Over clocking on the I7 memory



## jaggerwild (May 21, 2007)

Hey All!
It has been a while:wave:.

I was wanting to ask this question, and I am still and will always be a noob when it comes to over clocking especially with the new I7 socket. I know that the memory run at 1/2 the CPU speed so if the CPU was say 4.4Ghz then the memory would be 2200 Mhz right. So if my memory is 1600 what would be its limit to over clocking it? In other words is 1800 possible, what about 2000mhz. There are so many options in the bios, I could just keep changing my divider to keep the memory from limiting the OC per say? Kinda like the (old LOL) socket 775 right? Or will this limit me as to what I can or can not do with it?

Thanks!ray:


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## Aus_Karlos (Mar 10, 2007)

Depends on the RAM and what timings it will work at. Increasing frequency from 1600 to 1800 will be more than enough, at 2000 you wont notice much performance increase you can use this to tighten the timings.
However your slightly wrong about the CPU/RAM ratio, its actually Uncore/RAM ratio.
Ive got my RAM at stock settings at the moment but it because it helps at my current level of OC.
For an example of Uncore to RAM ratio i have my Uncore set at x21 (Close to 3200mhz) and my RAM at x10 (@ 1600mhz). Keeping a 2:1 ratio of these will keep your system stable allowing you to OC the core further.
Everytime you overclock the core the uncore will increase aswell. So change your RAM timings to keep it as close to a 2:1 ratio as possible.

What are your voltages.
Vcore
VTT/QPI
Core PLL
*DIMM voltage should be no higher than 1.65v*
Do you have line calibration on?
What about Turbo mode?


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## jaggerwild (May 21, 2007)

Hey Aus Karlos!

Vcore is 1.37(water)
VTT/QPI I left it stock 1.5
Core PLL stock 1.8
DIMM is 1.65
LineCali without Vdroop
Turbo was on

Right now I have loosened the timings as was trying to give myself room 11 11 11 24 74. 


> Everytime you overclock the core the uncore will increase aswell. So change your RAM timings to keep it as close to a 2:1 ratio as possible.


 Ok I'll try it in a while 2:1 ratio Uncore to Ram. I'm on a different computer and the I7 is not hooked into the internet so makes it hard to see what it is or running back and fourth.

Thank you!


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## Aus_Karlos (Mar 10, 2007)

1.40v for the core is around the maximum the i7 chips can handle 1.37v is fine, the Core PLL is where it should be, dont go over 1.86v for PLL the core just doesn't like it.
At this stage in your OC you should have LineCali On, it will help with system stability under load.
If i where you, you need to double check your VTT/QPI voltage, by default it should be at 1.30v, 1.5v is well over the top, the max it should be is 1.35v.

Hold on i think im getting confused are you overclocking an I7 CPU?


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## jaggerwild (May 21, 2007)

Actually it is a Xeon W3520.


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## Aus_Karlos (Mar 10, 2007)

Ok, so ive taken a look at the CPU specs, i would see if you can lower the Vcore voltage its a bit high for the Xeon, many people seem to be able to clock it to 4.2ghz (D0 stepping) with Vcore @ 1.27v-1.3v. (CPU max is 1.35v)

Still your VTT/QPI voltage should be no higher than 1.35v so please lower it you could damage the controller memory. (Double check that 1.5v is default first)
Same goes for the CPU PLL voltage, no more than 1.86v.

Also the same ratio applies to the Uncore/RAM. 2:1, however some M/B have locked Uncore multiplier when using a Xeon W3520 so you will have to adjust the RAM accordingly. 

Then when you think your system is stable run Prime95.
32-bit
64-bit

Seems the max temperature of this CPU (Cores) is between 75c-80c so make sure it doesn't go over, if it does then back the OC off a little. Also if the stress test fails do the same thing back it off 5mhz on the BLCK clock.


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