OC 4Ghz at very low temperature

[Sayso]

i tried the clock skew and it didn't have any benefit..was hoping to get my Vcore lower its currently at 1.28 for 4.2, have managed to get my QPI down to 1.275 so slowly getting there.
also tightened up my RAM settings to 8 8 8 20 @ 1600, when ever i try and run at 7 it crashes but as the cas timings are under spec im happy to lose out on the extra 200Mhz im missing by not getting the blk higher.
I would have hoped to be able to run blk at upto 220 on my board but im stuggling....

 

[reygjabla]

I think this one is a real one, but I haven't got any clue how it went pass 5.2Ghz !!! for i7 920 do !!! must be running under phase change.

Check the multiplier and the voltage. Amazing.

 

[DavyBoy]

Guys, do you think this is photoshopped?

http://valid.canardpc.com/show_oc.php?id=707679

Gotta be photoshopped guys, you can't unlock the multi on a 920 as far as I am aware.. if these chips CPU multis could be unlocked, it would be all over the overclocking enthusiast forums..

It doesn't seem make any difference to me when I knock the qpi/vtt voltage down from 1.20v to 1.11v.

You seriously don't expect to be able to run Vtt at 1.11v do you??

Saying CPU Clock Skew doesn't make a difference because you are unable to run Vtt at less than stock when o/ced to 4GHz is just plain stupid!!

I personally feel that using 100ps clock skew has made quite a noticable difference to my voltages, I could NEVER use 1.215v Vtt and 1.275v Vcore before, and the only thing that's changed is raising the clock skew, so this is the only thing that can be responsible for my lower voltages I would say..

@lettuce, I always set my RAM to 4500MB in LinX/IBT.. the more the better really.. no point in using less than 4000MB, though if you are using a 32bit OS I believe that it is retricted to only 2000MB I think.

 

[Gaidin109]

has anyone tried the ioh clock skew?, and if so was there any benefit?. I havent got the time to until later in the week. I've got my vcore down to 1.216v in cpuz and vtt to 1.91v so a marked improvement.

 

[bulldog147]

has anyone tried the ioh clock skew?, and if so was there any benefit?. I havent got the time to until later in the week. I've got my vcore down to 1.216v in cpuz and vtt to 1.91v so a marked improvement.

I would leave both cpu clock skew and ioh clock skew at default at 0ps and leave well alone. It make no difference. I am sure that Rich from ocuk might answer us about what benefit does it do ?

 

[JonJ678]

no point in using less than 4000MB, though if you are using a 32bit OS I believe that it is retricted to only 2000MB I think.

I think it should be 2gb, though it only seems to allow 1.87gb. Regardless it's a strong argument for 64 bit. LinX, the ibt clone, does it run under ubuntu by any chance?

 

[lettuce]

Yeah I think we really need to find out what CPU clock skew does, if people who set it to 100ps, can now get a lower vcore and qpi then why is that, it must be putting voltage in somewhere???

 

[OLDPHART]

Little help for oldphart, you go on about adjusting your QPI, is that the QPI/VTT SETTING IN THE BIOS.

Cheers

 

[Gaidin109]

Yeah I think we really need to find out what CPU clock skew does, if people who set it to 100ps, can now get a lower vcore and qpi then why is that, it must be putting voltage in somewhere???

Clock skew is the delay on CPU clock, adjusting it allows better stability between the CPU clocks and DRAM and IOH clocks. It compensates for the added voltage and frequency when overclocking.

Someone might be able to explain it a bit better than though.

 

[BigBruiserAl]

Little help for oldphart, you go on about adjusting your QPI, is that the QPI/VTT SETTING IN THE BIOS.

Cheers

yes mate QPI volatge in the bios

 

[lettuce]

Clock skew is the delay on CPU clock, adjusting it allows better stability between the CPU clocks and DRAM and IOH clocks. It compensates for the added voltage and frequency when overclocking.

Someone might be able to explain it a bit better than though.

So would that effect performance then, if you are increasing the CPU Clock Skew, then you would be increasing the delay of the CPU?

 

[Gaidin109]

So would that effect performance then, if you are increasing the CPU Clock Skew, then you would be increasing the delay of the CPU?

Not in a detrimental way, each component is working at a different frequency so what happens is that when one components ability to keep up with the increased frequency of another is compromised Clock Skew can be used to adjust this. Its just a timing adjustment.

By adjusting this it can help synchronize each component, especially the IMC and core clocks, thus making it more stable. (ps) means picosecond which is 1 trillionth of a second, so the delay is so small as not to impact in any real way on performance.

If your up on your Math or an engineer this link explains it in detail, but be warned its complex:

http://electronicdesign.com/Articles/Index.cfm?AD=1&AD=1&ArticleID=9611

 

[DavyBoy]

I would leave both cpu clock skew and ioh clock skew at default at 0ps and leave well alone. It make no difference. I am sure that Rich from ocuk might answer us about what benefit does it do ?

I don't agree bulldog, like I have been saying all along, after setting CPU clock skew to 100ps, I can now use considerably less Vtt, and I also managed to knock Vcore down a couple of increments as well.

I have tested these voltages before, and my system would BSOD after 2 passes of LinX or a short run of Prime, but with 100ps CPU clock skew, it is LinX/Prime stable, I've had it like this for a couple of days now, and have used my PC for gaming, watching movies, listening to music etc, and I haven't experienced one BSOD yet.

To say we should leave these settings well alone makes no sence to me whatsoever..

Also, do you worship rjkoneill or something, you are always expecting him to come and answer questions, no offence mate, but there are plenty of knowledgable people on these forums, Rich isn't the only guy who knows his stuff!!!

 

[rjk]

i am pretty good to be fair

 

[[OcUK] 007]

It pity that all Intel i7 core chipset could be great clocker, some don't and I think it really sad because the cpu chipset made by intel manufacturing should be the same cherry chip. I think it depend where the chipset made from, eg: china or uk or usa.

bulldog i do belive that there is only one chipset for i7 is this correct or have i been mislead somewhere down the beaten track????

the fact of the matter is that the chipsets are made by intel and have the same pitfalls that CPUs do, some are amazing, some are not so good

that is just how computer hardware works

 

[DavyBoy]

I didn't mean that to sound offensive towards you Rich, I know you are a very knowledgable guy, and you clearly know your stuff, but I just get the feeling that bulldog worships you, as he always looks for you to confirm things on here.

For him to say that us guys should leave settings in the BIOS well alone is nonsence as well imo, if tweaking something allows us to run with lower voltages, then why not take advantage of that?

@ 007 you are right mate, there is only one chipset available for i7 processors, and that is X58..

I think by chipset, bulldog meant processors, not an actual chipset.

 

[rjk]

probably

its ok DavyBoy

im only here to help - i dont claim to know everything

but you do learn a thing or two when you do 20+ overclocks a day

 

[[OcUK] 007]

davyboy imo you are right if something is there to be tweeked why not do it to achive lower temps

 

[Gaidin109]

i am pretty good to be fair

LOL

 

[lettuce]

So does changing CPU clock skew add any heat to the cpu? and does IOH clock skew help with anything.

Your right though my LinX failed after 20 mins, with 1.275 Vcore, i then changed CPU clock skew and it did 20 pass, result. Any other voltages i should tweak other than, ram, voce, qpi??