Overstepping the limits of QPI (Please Help)

ShiggsUnderground

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**NOTE: This is my very first time overclocking and even reading about overclocking**

I would like to overclock my future Intel Core i7 920 build from 2.66GHz to 3.6Ghz. I'm planning on building this after Thanksgiving and before Christmas, this year.

With what I have been reading about overclocking for the past month is that, with this processor...

- A BCLK of 200 and a CPU Multiplier of 18x should give me a CPU frequency of 3600MHz (3.6GHz).

- A BCLK of 200 and a Memory Multiplier of 8x should give me a Memory Frequency of 1600MHz (which is what I want as I am planning to buy RAM

at exactly this speed).

- A BCLK of 200 and an Uncore Multiplier of 16x should give me an Uncore Frequency of 3200MHz (twice the speed of the Memory Frequency from

what I understand it needs to be).

- A BCLK of 200 and a QPI Multiplier of 36x should give me a QPI Frequency of 7.2GT/s or 3600MHz (Since 36x is the default value with this processor).

I'm a fan of nice, even numbers. :)

Now here are the questions I have been searching to find answers to, for weeks now:

When I multiplied 200 by 36, I got 7200MHz for the QPI.

If this is true, then that would mean that not only am I going over the 2.4GHz/4.8GT/s limit for the lowest-level QPI, but I'm also going over the 3.2Ghz/6.4GT/s higest-level QPI which I hear is no longer exclusive to the i7 965 Extreme, but on Retail i7 920s as well. What effect will this have, if any, on the motherboard or any other module in my system if I am exceeding the top 6.4GT/s limit? Does this now mean that my QPI frequency will run at 7.2GT/s even though there may be physical limitations, will it be capped at 6.4GT/s somehow, or will my QPI speed simply be running faster than recommended and eventually burn out my motherboard or CPU?

I'm assuming the QPI was not made with such a high speed in mind. I don't wanna burn out my first motherboard and/or CPU on my first build. Any answers would be greatly appreciated.

Thanks, in advance.
 

overshocked

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Dude, dont worry about qpi....

It is really easy with voltage. So you can give it a ton of voltage to get it to 7.2gt/s.

This is an extremely easy CPU to OC. You look like you have done your homework so you should have no problem OCing it.

But may i suyggeest if you are waiting so long to jbuy the system then why dont you wait for the 32nm??
 

ShiggsUnderground

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Yeah, but even if I add more voltage to get my system to work at 7.2GT/s, what adverse effect will this have long-term? Will my system even be running at 7.2GT/s? What is your i7 920 system's QPI running at? I'm sure I'll be able to make it work, but I am a lover of knowledge. I like to know exactly what I'm doing and exactly why something will or will not work.

The new 32nm chipset looks interesting but from what I see here,

http://en.wikipedia.org/wiki/Intel_Westmere#32_nm_processor_architecture_.22Westmere.22

I won't be missing anything. I really need this computer by the end of the year anyway. I've been working on a Pentium 4 with 512MB RDRAM from 2002. :eek: Yeah, I know! Needless to say, I'm long overdue for an upgrade and now that I'm out of college, I need one ASAP so I can get working on my portfolio. Time is of the essence. Those loans don't wait for anyone and finding a job takes time! :sweat:
 

Dangerous Beans

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"Will my system even be running at 7.2GT/s?"
Unless it says it will on the box; it might or it might not. Have a poke around on the net, if a fair few people get theirs that high then it is probably likely, however if there are only a few then it doesn't look as likely. (the x58 is designed to run at 6.4, so the processor is probably the limiting part)

"Yeah, but even if I add more voltage to get my system to work at 7.2GT/s, what adverse effect will this have long-term?"
It will kill your processor and/or mobo. Do some reading, keep it all cool and try to keep the voltages down where possible. The more voltage you give it and the hotter it runs the faster it will go, though provided you don't push it too hard it should be obsolete well before it dies.
Also, you may be better off running at a slightly lower speed, but a much lower voltage. for instance my e8600 needs 1.55vcore @ 4.5ghz, but only 1.4vcore @4.3. i'm not sure a 200mhz gain is worth 0.15v

Also, don't get too obsessed with even numbers. take it slow, watch your temps and voltage, and be willing to settle for 200mhz slower instead of a dead CPU.
 

ShiggsUnderground

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That's good advice. As a matter of fact, I've been coming around to the idea of just running the processor at 3.2GHz. That seems safe to me and anything above 2.66GHz is a gift anyway. I don't play much games, but I do a lot of photo work. Having Adobe products running smoothly is a top priority for me and I imagine that there are other parts of a build that can contribute to this other than mere clock speeds.

Dangerous Beans, do you have an i7 and if so, what is your QPI speed?
 

Dangerous Beans

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"Having Adobe products running smoothly is a top priority for me"
Is that even possible? I usually assume anything with adobe logo will crash at least once per day :p

I don't have an i7, still on core 2 (considering what I use my computer for I need clock speed rather than more cores; so i went with a dual core).
From what i can see, the x58 chipset is designed to run up to 6.4gt/s so getting it to 7.2gt/s is only an 12.5% increase. that should be fine. the cpu however is only designed for 4.8gt/s, so going to 7.2 would be a 50% increase, which is pushing it a bit harder.

Don't get too set on any number, instead do the overclocking, see what you can get and then decide what to run it at. you may get a 920 that does 3.6 with minimal voltage increase, one that struggles to hit 3.6, a new job which lets you replace your cpu every 6 months ;)

these people here have a whole pile of results, mostly 3.8 to 4ghz on air at 1.4vcore.
 

overshocked

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Trust me , dont make the mistake of buying to early! The 32nm are expected to hit eat the end of this year or q1 2010.
 

ShiggsUnderground

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Yeah, that is kind of funny. I don't believe there was ever a time when an Adobe product ran smooth for me. Then again, I was never developing on current hardware. :) Thanks for the advice. I will think about what you said regarding QPI.
 

ShiggsUnderground

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overshocked, the Westmere chips up first seem to only be dual core, with the quad-core variants supposedly out mid-2010.

Here is where I got that info: http://www.pcper.com/article.php?aid=668

As much as I would like to, I can't wait any longer for a new PC. I will only give the wait time till the end of the year. If nothing happens, then I will be fine with the current i7 and wait it out for Intel's next two 'tocks'. It looks as though they took the QPI out in favor of DMI (whatever that is) on the new variants. Great... something else to learn lol. :wahoo:
 

Dangerous Beans

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As I understand it, because westmere basically moves most of the north bridge functionality onto the cpu die, it now has the Direct Media Interface linking it to the southbridge.

I say upgrade now, if you wait there will always be something else to wait for. Though this is from someone who bought socket 939 just before AM2 came out, and a socket 775 6 months before they will be phased out.
 

ShiggsUnderground

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Thanks Dangerous, I've decided to not wait. I'm going for the i7. I just have one more question. Since Intel 'unlocked' the QPI frequency to 6.4GT/s on the retail chips, does that mean that the i7 did 6.4 to begin with and not merely 4.8?