Read it better. He's laughing at his own mistake. :shakes:Quote:
Originally Posted by Bobbylite
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Read it better. He's laughing at his own mistake. :shakes:Quote:
Originally Posted by Bobbylite
:rolleyes: sarcasm my friend :eek:Quote:
Originally Posted by zlojack
:D You need to put the sarcasm smiley in, then.Quote:
Originally Posted by Bobbylite
Or the irony mark :rofl:
less BS more Xtreme ; 0 :welcome:
Hey there!Quote:
Originally Posted by JPQY
Well, strange things happen every day and today was one...
First things first, I love this chess simulation. It really loads the cores 100% (reported usage never fell below 99.2% on any of the threads, averaged around 99.8%), it is more representative of real life than Prime or any of those other things, and it really generates maximum heat on all cores. So, now that I am done praising you on to my testing...
I decided to give your program a whirl to see what kind of results I can get. Naturally, anything with 20x multiplier was a no go so I tested with 200x19, 212x19, 216x19, and then finally tried to do 220x19. Well, all went very good until I got to the last test. I upped the volts in BIOS to 1.5V vcore, 1.475V-ish QPI/DRAM. I booted, ran for a couple of seconds, then my computer just shut down and I could not reload into Vista. I ended up having to pull the battery on my R2E :eek: and manually restore BIOS2 to BIOS1. After doing that, I reinstalled BIOS 0804 to BIOS1 and for the first time since I bought this board after updating the BIOS the board actually rebooted itself successfully and prompted me to set the new BIOS settings! Whoa! :shocked:
It gets better. So I decide, what the heck, I do not have any of my profiles any more, how about I just set X.M.P for memory (sets DRAM voltage to 1.65V and QPI/DRAM to 1.35V), leave all timings as is, all other voltages to Auto and set the BCLK to 200 and multiplier to 20x. I booted, started your app, ran it, and crashed about 4 minutes in. I was like "crap, here we go again with the 20x multiplier" but then I remembered reading somewhere that somebody said QPI/DRAM voltage should be always no less than 0.01V and no more than 0.03V away from vcore. So I grabbed my MM, measured the vcore voltage, then set the QPI/DRAM volts to be exactly 0.025V apart. Booted back into Vista 64 with the new settings, ran your app, and no crash! None, nada, it keeps going strong! I stopped it about 15 minutes in just because it had already stabilized on load and temps 5 minutes prior to that. Impressive! :shocked: It looks like I at least managed to find something that makes 20x multiplier work.
Anyway, here is the screen (I forgot to save results)...yes, I am sure the volts can be lowered, but quite frankly I do not care at all. I am using all auto except X.M.P profile and I have manually upped the QPI/DRAM from 1.35V to 1.40V. Cooled with a CoolerMaster V8 using AS5, in a toasty 23C room with the computer stuck in a corner where there is barely any airflow :p
200x20 baby :up:
ummm, R2E bios 0804? where??!?
edit: nevermind, found it.
Lol, I was just about to post it...Quote:
Originally Posted by bmilos
http://vip.asus.com/forum/view.aspx?...Language=en-us
Yay! Improved RAID controller compatibility... Grrrr.....
Yay! We alls needs ours RAIDs controllers. :p:Quote:
Originally Posted by bmilos
Anyway, back on topic...
Ok Mr. Moderator ;0 :welcome:Quote:
Originally Posted by clip
:shakes:
pfft. :down::up::shrug:
That damned scratchy wool mod hat..Quote:
Originally Posted by clip
Ok guys, calm it down or do I have to play Attilla the Hun here?
try a little patience and when you fingers want to type something nasty go get a cold drink and cool down before you post.
No one is perfect so if and when someone says something that isn't quite right cut them a little slack in your reply.
remember, no matter how smart you are or how much you know there is someone on this forum that knows more and is smarter.
Now friends first huh?
Thanks for reading.
Well said.
Anyway, with the new bios and realizing that I only had 2 of 3 fans running on my rad, I am running prime for about 25 minutes @ 4.2 with a 21 x 200 @ 1.41250 and a vtt of 1.53750.
Temps are 80c solid under load and things are looking good.
Typical ASUS you shouldn't buy their boards if you need tech support from ASUS for real.. We are all aware that there tech support is a joke but there boards and bios updates are no joke... In addition there is a new bios out for the P6T Deluxe bios 1003 you can get it here:Quote:
Originally Posted by derektm
ftp://ftp.asus.com.tw/pub/asus/mb/LG...ELUXE-1003.zip
here's 3.6Ghz 20x180 8 hours prime blend 64bit stable with 12GB of ram.
edit: using the Z18 bios. temps are 68C, 68C, 67C, and 67C on the cores.
i stopped prime after 3 hours last night @ 4116mhz HT on, turbo on, vcore 1.45v, qpi/vtt 1.435, dont wanna push it more till i know more about voltages, i still wanna see what clocks i get with HT on and turbo off, then HT off and turbo on and then HT off and turbo off
mine is the same , hates 20 x multi, but i think they just need more voltage hope future bios will be better for usQuote:
Originally Posted by Lukee
i agree 100%Quote:
Originally Posted by dejanh
whats the longest you have run prime at and at what voltages and clocks, most of your prime screen shots that i have seen havent been very long, sorry if i have missed them,Quote:
Originally Posted by mascaras
stable to me is at least 8 to 10 hours of prime even longer, as i have failed prime even after 3 to 4 hours before
cheers guys :D
Hey, quick question as I've been away from the discussion for several days. Who has gotten the highest OC thus far without volatage increases? I've been wondering if one of you guys with those "golden" chips that OC like nuts ever tried that out.
I tried again last night and can't get a 20 multi to work at anything reasonable. Oh well, I guess I'm stuck until possibly another bios update.
Yeah the 1003 bios for the P6T Deluxe doesn't seem to fix the 20 multi problem either.. Seems so strange that I can rock 210 or 211 at the 19 multi but can't do 200 at 20...
200 x20 is working fine here. Maybe its a per chip thing?
Same here. In fact, if anything 20x200 is more stable for me than either 19x211 or 21x191.
giga x58 ud5
patriot 9-9-9 DDR3, 6GB
i7 920, 'C0' revision
Tuniq tower 120
Vista 64 here.Quote:
Originally Posted by dejanh
Quote:
Originally Posted by Bobbylite
Quote:
Originally Posted by roller11
is that with HT on ?
Yes, with HT either on or off.
Does having HT on affect the 20x multiplier issue some are having?Quote:
Originally Posted by freshy
either works, ht just needs a vcore bumpQuote:
Originally Posted by freshy
Quote:
Originally Posted by Bobbylite
On average, how much of a Vcore bump?
So to achieve stability with HT on versus off at the same Ghz, you need a vcore bump? That makes sense because my rig is 12 hours Prime stable at 1.39v with HT off but I've tested it at 1.41v@4Ghz with HT on and had issues.Quote:
Originally Posted by Bobbylite
quite a bit actually like .03-.04
It could be a per chip thing but it could be more likely a per motherbard BIOS thing. The guy that posted above you has an Asus P6T and you've got a giga board.Quote:
Originally Posted by Bobbylite
Makes sense. Oh well, my rig is used for gaming exclusively I could care less if it can handle 8 virtual cores maxed out for an extended period of time. No game comes close to maxing 4 cores so I'll leave it as it is. I'm going to try dropping the voltage even more and see if it stays Prime stable on four cores.Quote:
Originally Posted by Bobbylite
Do you have ACPI 2 enabled?Quote:
Originally Posted by Aberration
Quote:
200 x20 is working fine here. Maybe its a per chip thing?
I think that it may be a per-chip thing, except I have no explanation for it short of some chips actually having faults. However, I'd think this would be a pretty high number of faults as both i7 940s I use have the same problem and they were picked totally at random, and a lot of other people are reporting not being able to stabilize anything with 20x multiplier. The flip side of this is that the failure rate is surprisingly high for it to slip past Intel's QC which then points to the boards being the culprits. Could anyone confirm that this does not in fact happen on non-Asus boards?Quote:
Same here. In fact, if anything 20x200 is more stable for me than either 19x211 or 21x191.
In terms of stability, In theory, 20x200 should be more stable than 19x211 or 21x191 as one pushes the BCLK close to the limits, and the other pushes the multiplier to the limit (at least for i7 920).
Anyway, I am again failing on 20x200. It seems that whatever happened yesterday when I ran it was a fluke. I managed to do a few runs with it fine, but now again 20x200 is not stable where as even 216x19 is stable (but too hot for my taste). Running on R2E here...
Chip or mobo either way it is BS. If it is the chip, Intel will probably just fix it all in the next stepping as opposed to providing any kind of good workaround. If it is the mobo, I am not expecting a fix ever.
I agree this is very weird. My i940 with any bios and turbo off, will run 4ghz, 20x200, 21x191, 22x182 all at exact same vcore of 1.35bios and all 12 hrs prime stable. maybe if people list mobo, all settings, or ? cpu batch #'s and see if anything in common on those having problems with 20 multi vs not. Be interesting if could find any common issues. (I cant test with turbo on since 20x200 turbo on i940 is 23x200, 4.6 is not going to prime.)Quote:
Originally Posted by dejanh
Is vcore the only important voltage? Do other voltages need to be increased to achieve 4.0+ ghz?
My first post, max prime stable 11+hrs for my i7 e965,
HT enabled max volts for vcore, qpi and vdimm: 1.55, 1.3 and 1.64
Is this too high vcore for up to 12hrs/day?
max cpu v as stated here http://i4memory.com/wp/article/422
Cooling Method air - Noctua U12P sandwiched with two Ultra Kaze 120s (fans turned down to tolerable db level).
Real temp max was 97 – all cores stayed at “ok” status.
screen capture hopefully follows -
@ Furious: Rasing my QPI/Vtt to 1.4v allowed me to lower my vcore, pll you may or may not need to bump as well
If I turn off HT I can do better -
Bobylite - raise qpi to 1.4 to get lower vcore?
I will give that a try, thanks!
do you have an i7? Because this is not true, there is a careful balance of voltages that need to be met.Quote:
Originally Posted by anthonygj
@ steve. I suppose if intel says 1.55 max, then its 1.55 max. I wouldnt feel safe running it that high or hot. Sure you need that much vcore? Try toying with your other voltages more. QPI especially
1.315v max for qpi, and 1.55v max for vcore
SteveRo...nice to know one can run stable at 97C, mine runs hots as well, even though on water, at 1.5 vcore I would probably be near there myself.
Hyperthreading off does allow you to run same mhz with less vcore partly b/c less threads, but also because you are using F3 bios which is giving you turbo with 4 threads (turbo is off with hyperthreading enabled), and the turbo multi - extra mhz (134 in your case) comes at a cheaper vcore price, for unexplained reasons.
Point is you could update to bios F4j on extreme, enable turbo, and run at same mhz (prime loaded) with probably less vcore than F3 bios, b/c the extra +1multi which again for whatever reason gives same mhz with less vcore that non turbo +1 multi.
Ok, thank you. I have tried Vcore up to 1.4 on my 965. However my computer crashes in prime 95 @ 4.0ghz 1.4v. That seems like way more than anybody with a 920 requires. What is the max safe vcore on a Core I7?Quote:
Originally Posted by anthonygj
I am going to experiment with Turbo and see if that will lessen the need for vcore.
he has an extreme = unlocked multi so he can set it at whatever he wants
absolute max specs per intel data sheet:
My Corsair memory is reading a DRAM voltage of 1.66v. Given that Intel has stated that anything over 1.65v can damage the CPU, are there any reports on whether the .01v overage poses any danger?
How can Vcc have a negative min... :shrug:Quote:
Originally Posted by rge
Easy. They're simply recommending that you don't undervolt the chip by more than that amount.Quote:
Originally Posted by 003
No. You are not running over 1.65V. If you took a MM to your board you would see that your memory is likely running at 0.02V less than that, so about 1.64V. Either way, it is so close that it makes absolutely no difference. I think a BIOS update changes this as well.Quote:
My Corsair memory is reading a DRAM voltage of 1.66v. Given that Intel has stated that anything over 1.65v can damage the CPU, are there any reports on whether the .01v overage poses any danger?
Well, allow me to give a few details then about my setup...Quote:
Originally Posted by rge
Rampage II Extreme, 0804 BIOS (tried all others as well with no effect) running a Core i7 940...
Posting settings for 20x200 is irrelevant as no combination of settings works. For other combinations that work (e.g., 19x212, 21x191) it is your standard things, vcore, qpi/dram, dram, loadline, etc.
Someone please correct me if I'm wrong, but as far as I know the DRAM Bus voltage can go over 1.65 as long as it remains within 0.5 volts of the QPI/DRAM core voltage.Quote:
Originally Posted by Classic Satch
This is pure speculation. Until there is an official confirmation from Intel on this you are pretty much safe to assume you are cooking your CPU by going over. Either that or you take the plunge in the deep, cross your fingers, and hope for the best. I just know that if my R2E puts a big red warning that says "do not go over this" I probably should be a bit worried.Quote:
Originally Posted by BiOvOrE
Just my $0.02.
Lol, I agree. And thank you for your response to my question on my RAM voltage.Quote:
Originally Posted by dejanh
It was confirmed by the intel rep on XS... forgot his name, but I'm sure somebody can find where he says that.Quote:
Originally Posted by dejanh
I've only seen this coming from other forumers, not from official Intel reps. It makes no sense anyway because if that was trully done so, then why not just make it so that your QPI voltage limits your DRAM voltage. That way if you up QPI voltage you get more room to up DRAM voltage.Quote:
Originally Posted by 003
Actually a few posts up you can read that table that states 1.85 maximum safe for Vdimm voltage as long as you have the max safe Vtt of 1.35 (the 0.5v margin.)
14 hours prime still going @4.1ghz, HT on, turbo on , might stop it :up:
Well, the best I can do with either 20x multiplier or 20x + turbo is 195 x 21
Freshy - Looks like we are similar. i ran Intel Burn test for a while and that was stable, and now I'm running Prime 95. Only 45 minutes into it, but normally my system freezes in 5 max so this is a great sign.
I'm putting her under water this weekend so we'll see what temps are then!!
Indeed you are right. So why the heck are they saying to limit DRAM voltage to 1.65V? Maybe 1.75 is reasonable considering that absolute max is 1.875V.Quote:
Originally Posted by D3mon_Hunt3r
By the way, I spent some more time looking into the 20x multiplier issue and I think I am on to something...I posted this in another thread but this one is a lot more active so I'll bring it up here just in case...
Basically, after some more tests, I am starting to think that this has something to do with heat. If I lower the ambient temperature I can run stress testing longer at 20x200 then when I leave it at normal. Also, if I crash at 20x200 and then restart to try the run again, I cannot do it. But if I turn the system off for a few minutes, then power it on, I can run 20x200 again. Why in the heck would this be the case though when even higher volts and temps have been stable under say 19x216? Could something be making the CPU too sensitive to heat at 20x200? Some protection circuit tripping when it is not supposed to? Any ideas why this would be the case?
Pfft, speculation...Quote:
Originally Posted by dejanh
Anyways, my latest stable(ish) overclock on air for those interested.
http://img381.imageshack.us/img381/3...turedh0.th.jpg
Stable for an hour or so at this stage. vCore is 1.385 and QPI/DRAM is 1.35. The QPI/DRAM core voltage seems to have more effect on stability at the ~4Ghz range for me. Gonna Prime overnight and see how it goes.
Here is my chip @ 4.2 all 8 threads 1.45 with the same block 5hrs+ into a prime run not even close to 100c. My chip idles at 33c are you still getting high temps?Quote:
Originally Posted by managerman
yep , but you got HT off ? and also lower voltagesQuote:
Originally Posted by Lukee
that last prime test for 14 hours i done @ 4.1ghz i had the vcore 1.45v and the qpi/vtt 1.435, thought id try drop voltages a bit got 4.1ghz stable @ 1.425v vcore stopped it after 5 hours prime, im just trying to get qpi/vtt down a bit now , so priming now at 1.425vcore and 1.375v qpi/vtt, see what happens, i really think we gonna hit 4.2ghz sooner or later, might try give it a bit of qpipll v next run @4.2ghz, but first i wanna try drop voltages as much as possible for 4.1ghz
and under water sounds good :up:
edit...dejanh i really dont think its a temp issue as my temps are the same even with the 20 x multi , but it just isnt stable, i really hope a newer bios fixes it, also i was just reading back and roller said that his 20 x 200 works fine his is a CO revision, mine is a co/c1 revistion,
Freshy, I agree. It is only a matter of time we hit 4.2.
Yes, HT is off. I figured that I need to find a stable OC with HT off first, then I can turn HT on, but to be honest, I play mostly games and do some encoding. What concerned me was the temps without HT on. I wanted to wait until she was under water to try it with HT.
Are these overclocks 24/7 stable or we just playing around? I just sold of my 780 q9550 combo and i'm looking to pick up a rampage 920 combo was wondering if i should expect 4ghz.
I will be wc once they release the hold down plate for my fusion.
bootsy what is you WC setup, nice work
I would need to test mine a little bit longer, but Intel Burn Test was stable for about 10 runs and Prime95 small FFT was stable for a bit over 2 hours so a little more testing is needed, but to be honest, I'm not on the PC more than 3 -4 hours anyways, so for ME it's stable.Quote:
Originally Posted by modboxx
Well, I saw the issues some were having with the 20x multiplier so I upped the Bclk to 211, dropped the multiplier to 19 and lowered the voltage to 1.39. 12 hours later of Prime95 and still stable with HT on.
http://i210.photobucket.com/albums/b...ch/Test3-1.jpg
Time to drop the voltage further and retest.
just crashed after 1 hour of prime @ 4.2ghz HT on, turbo on :shakes:
turbo off tho ha classic ?
Nice. I was able to get 211 x 19 to work, but only with HT off.Quote:
Originally Posted by Classic Satch
I'll try it with Turbo on once I find the lowest voltage that I can run 4.0 stable with. I don't think Turbo is that important tbh.Quote:
Originally Posted by freshy
I had tried 200x20 with 1.41v and it kept crashing after about 30 minutes. Lowered the multiplier and voltage and upped the Bclk and whaddya know? It's stable. Go figure. :)Quote:
Nice. I was able to get 211 x 19 to work, but only with HT off.
199 x 19 + turbo 4.179ghz hope its still going when i wake up :eek::shrug:
@Bootsy - what are your other settings? I am running at the same 200x21 @ 1.43750 on a GTZ too, and my load temp is about 88c. Is the CPU the only block in your loop? I also have my NB in my loop. Maybe thats the root?
With all new F4 bioses TDP unlimited turbo... need to find settings for those. F3 sweetspot on mine was 1.35 bios 1.31 load for 4/4.2 turbo.
On bios F4j, 1.38 bios 1.34 load for 4.1ghz 8hrs so far...settings on pic where I can remember them myself:p:
Need 1.39-1.4 bios for 4.14, and ? 1.42 bios for 4.2...have to decide between those after figuring out exact settings.
Wow, I'm comparing temps of you guys with similar setups and it looks like my Exos-2 LX is holding up pretty well. I was too lazy to build a custom water cooling system and went with the LX and a Apogee GTZ water block for my new build. Comparable performance from what I can see so far.
Question: What were your temps at stock speed before you began to OC? I'd like to compare my stock-clock temp to yours before I OC and then compare my OC temp to yours and see how they compare.
I believe they were around the 30-33 range, depending on the core. Of course, my new 920 was only at stock speed for as long it took to load Vista 64. :p:Quote:
Originally Posted by Hot'n'Chilly
Ok, I think I finally have some answers to the 20x multiplier instability and a number of other issues many users are complaining about. You will have to follow me here as this is not that simple, but it makes a lot of sense and all of my testing to date has actually confirmed it. I have spent a lot of time figuring this out and I really hope that this will help people. Indeed, I am now able to predict ahead of time what settings will POST, what settings will not, and approximately which component will need to be juiced up higher to result in a more stable system. Furthermore, this will be a very thorough overview of Core i7 overclocking that will expose some serious limitations, particularly on the i7 920 and i7 940 parts. It is all primarily linked to the Uncore and QPI speeds.
First off, I will use the Core i7 940 for all of my examples. Core i7 920 and i7 940 are for all intents and purposes the exact same chip, but the i7 940 is just factory clocked higher. These are most likely not higher binned chips, and even if they are by some chance it really does not matter. You will soon see why. In essence, same holds true for the i7 965 EE though they are certainly higher binned and quite likely somewhat more forgiving when overclocking. The fact that they can overclock using an unlocked multiplier is a huge bonus for this chip.
For details on each of the CPU specifications see Intel's website and tech specs/data sheets. I'll just briefly mention the specs here, for reference.
Core i7 920 - 2.66GHz, 20x133MHz, 4.8GT/s QPI (2.4GHz), QPI multiplier 18x (18x133MHz)
Core i7 940 - 2.93GHz, 22x133MHz, 4.8GT/s QPI (2.4GHz), QPI multiplier 18x (18x133MHz)
Core i7 965 EE - 3.2GHz, 24x133MHz, 6.4GT/s QPI (3.2GHz), QPI multiplier 24x (24x133MHz)
The key thing to remember here is that for Core i7 processors everything is interconnected, much like in case of AMD processors. Therefore, changing the BCLK speed affects everything from core speed, to QPI link speed, to Uncore speed, to memory speed. The key elements and the limiting ones here are the last three, the QPI link speed, Uncore speed, and memory speed. Particularly, the QPI is the limiting factor for the other elements as the highest stable QPI link speed for the current Core i7 processors is 8.0GT/s or 4.0GHz for 99% of systems out there. Some exceptions have been observed, but these are extremely rare. This may also be chipset dependent limitation and it is possible that newer chipsets supporting Core i7 will not have this limitation. Anyway, enough introduction. Let's get to the details.
First let's look at the relationships between QPI, Uncore, and DRAM speeds.
DRAM speed must be in a 1:2 ratio or less to Uncore speed which in turn must be in 1:1 or less ratio to QPI link speed (8:9 Uncore to QPI or lower is preferred as the more you approach 1:1 the more unstable the system becomes).
So why Uncore to QPI ratio of 8:9?
I derived this ratio from Intel's specifications on Core i7 processors. Highest supported memory for Core i7 is 1066MHz with a QPI of 4.8GT/s or 2.4GHz. According to processor specifications then, Uncore would be running at 2xDRAM (or 2x DRAM multiplier, in this case 16x) which results in an Uncore speed of 2132MHz. When you take the ratio of Uncore to QPI you will get 2132:2400 or approximately 8:9.
I can run my Uncore higher than QPI and I am not seeing any problems. How come?
This is possible. In my testing this proved to be less stable than keeping Uncore speed below that of QPI. However, more importantly I found that running Uncore and QPI in a ratio more than 8:9 and approaching 1:1 made the system quite unstable, especially with added stress when overclocking. Furthermore, it is quite likely that running QPI lower than Uncore results in some performance degradation (I did not test this however). Finally, it is important to note that this flexibility is in a large part not there on the non EE parts as you do not have control over core multipliers to the extent where you could be running Uncore very high and QPI link very low as was shown in this example:
http://www.xtremesystems.org/forums/...79#post3491979
As a general rule of thumb I did not want to test combinations that fall way outside Intel's specifications, that require voltages approaching critical values according to Intel datasheets, etc. Most users are looking to overclock but still run a long term stable system and not just get the highest benchmark score. Naturally, a lot of instability issues can be resolved by sufficiently increasing voltages to the components experiencing problems but this is very risky and not sustainable for long term use. To be safe I would strongly advise staying within the limits specified by Intel (can be seen here http:// www.xtremesystems.org /forums/showpost.php?p=3435336&postcount=13) and recommend staying at least a good percentage below the absolute maximums.
Now that we know this relationship, let's dive right into some of the most common issues with Core i7 processors.
1. Why is it that I cannot run my 2000MHz memory in my new Core i7 system?
To understand this note the maximum QPI link speed we mentioned earlier. Using the simple ratio we defined, we can see that with the maximum QPI link speed of 4.0GHz we can have a theoretical maximum Uncore of 4.0GHz and a maximum memory speed of 2.0GHz. These however are only theoretical maximums and are by no means guaranteed. For starters, QPI and Uncore cannot be run at the same speed as any clock oscillations can result in a crash if the ratio of QPI to Uncore ever falls below 1:1. Therefore, Uncore must always be below QPI to avoid this, and preferably below the 8:9 Uncore to QPI ratio to guarantee stability. Consequently, if we cannot achieve 4.0GHz Uncore, this means that we absolutely cannot achieve 2.0GHz memory and we can therefore not guarantee any stability for 2.0GHz memory. Technically, the maximum DRAM speed for a stable system is equal to ((Max. Uncore) / (Safe QPI:Uncore Ratio)) / 2 or (4.0GHz / 9:8) / 2 = 1.777GHz. In between 1.777GHz DRAM and 2.0GHz DRAM you are likely to experience some level of instability over the long term. Past 2.0GHz you are just plain lucky.
2. Why is it that almost none of the X58 boards can reliably clock the BCLK over 222MHz?
The answer to this again lies in the QPI link speed. At default (and lowest possible multiplier) for QPI of 18x the QPI link speed becomes 18x222MHz or 3.996GHz (4.0GHz). As we have already stated earlier this is dangerously close to the maximum QPI link speed and is therefore very unreliable. Anything higher than 222MHz and you have exceeded the current QPI maximum so in 99% of cases you will experience no POST. For this matter, a simple guideline is that any BCLK combined with a QPI multiplier that is at or very near maximum 4.0GHz QPI link speed is a candidate for no POST or instability.
3. What the heck is the deal with the 20x multiplier then?
This one is a real kicker (in a funny way). Yes, 20x multiplier is special, in more than one way, but mostly in the way people are trying to use it. You see, there is nothing wrong with the 20x multiplier. Indeed, it works, just like all other multipliers, perfectly fine. It is the DRAM multiplier and BCLK that people are combining with it that causes problems when combined with the QPI multiplier and the Uncore speed. At 20x200MHz, our default memory multiplier is 8 and our memory is at 1600MHz. The Uncore speed becomes 16x200MHz or 3.2GHz (or 2xDRAM at minimum). Therefore, remembering our (safe) ratios of 8:9 Uncore to QPI we see that the QPI link speed must be a minimum of 3.6GHz or higher. In case of 20x200MHz the Uncore and QPI are exactly in this ratio and with the added stress on the core, cache, IMC, DRAM, etc. this becomes a problem. At this point clock oscillations become much more prominent and if the QPI link speed falls below the 9:8 ratio to Uncore at any point in time combined with the added stress on the components the system can and likely will become unstable. Hence, at 20x200MHz with a default memory, Uncore and QPI multipliers we cannot really have a 100% stable system. So you say "just up the QPI link speed then". Not so fast. Remember our multipliers for QPI? They start at 18x, and the next is 22x, and so on. Unfortunately, 22x200MHz results in QPI link speed of 4.4GHz which results in no POST. Therefore, this cannot be done. Indeed, the highest reliable BCLK for default multipliers when using 20x core multiplier is 181MHz which with a 22x QPI multiplier would result in 3.982GHz QPI link. Even if you could set QPI multiplier to 20x, this would still not work for 99% of the boards out there as your QPI link would still be 4.0GHz. So what is the solution you ask? Memory multiplier. It needs to be lower. 1600MHz DRAM is approaching the maximum stress point for 20x200MHz core settings as it pushes on the limits of Uncore and QPI too much. By using a lower memory multiplier (say 6x if possible) the DRAM speed would become 6x200MHz or 1200MHz, Uncore could then be set at 2.4GHz with a lower multiplier which would then allow the QPI link to stay at 18x and well below the QPI link limits but still in a stable ratio to the Uncore.
So there you go. A couple of answers to some of the most painful Core i7 questions. Unfortunately, if you can read between the lines, this does not bode well for anyone owning a Core i7 940 or a 965 EE. For all intents and purposes Core i7 920 performance and Core i7 940 performance are identical. Core i7 965 EE has more flexibility but only because of its unlocked multiplier which allows it to use lower BCLK speeds and DRAM multipliers to achieve higher clocks. Otherwise, it is no different than a Core i7 920 or a Core i7 940. Like I said before, this may also be a chipset imposed limitation, and the processors themselves may be a lot better but at the moment, the state of the affairs is like this.
I have put a lot of thought and work into this so please if you want to comment do it constructively. I welcome any feedback and I hope that this will help a lot of people. It has helped me now to have a rock solid 4-core/8-thread, full 64-bit instruction set 4GHz air-only overclock on the Core i7 940 combined with a nice 1800MHz on my Corsair Dominator triple-channel sticks while keeping all of the voltages within Intel's recommended settings (i.e., DRAM is below 1.65V, QPI/DRAM is below 1.4V, and Vcore is below 1.39V under 100% load).
I would seriously ask you to marry me if you could make a Core i7 overclock calculator that takes into account all the factors and variables you described.Quote:
Originally Posted by dejanh
I understand what you said, but it's just too much info for me to remember when sitting down at the BIOS, unless I have a printed copy of what you wrote on hand, a scratch sheet of paper and an algebraic function calculator such as the TI-34. :clap:
That's some excellent observations there dejanh. :up:
So what we need is lower QPI multis to really push Core i7 to it's full potential.
I kinda miss the independent memory handling of nVIDIA chipsets.
The limited multis of intel chipset(and i7's mem. controller) are somewhat frustrating.
How you got your Corsair Dominators to 1800mhz baffles me; I cant even get an extra 50mhz out of my 1600MHZ kit.
Hehe, I can try but I do not have access to all the chips and a few boards. I only had access to the non-extreme parts and a R2E board (mine). I would need to know all of the multipliers that are available for all chips and boards to make it a trully reliable calculator.Quote:
Originally Posted by 003
In the meantime, you can also see what will be fixed in the next stepping of Core i7 here - http://download.intel.com/design/pro...pdt/320836.pdf
Nothing that will improve overclocking though...
Yeah, lower QPI multipliers would really help. But ideally, whatever is imposing the QPI limit needs to be removed. I doubt it is the CPU itself. I'd be betting it is the X58 chipset.Quote:
Originally Posted by Nanobot
On the note of the Dominators, to get 1800MHz out of the Dominators I had to drop the BCLK to 180MHz, use a 22x muliplier for Core i7 940 (default), use a 10x multiplier for DRAM, set Uncore to 3.6GHz, and set QPI multiplier to 22x. This nets me 3.96GHz core (4.14GHz turbo), 1804MHz DRAM, 3.6GHz Uncore, 3.96GHz QPI all on healthy voltages and air. My ratio of QPI to Uncore is sitting at 3.96:3.6 or 1.1 which is not ideal but likely stable enough for long term use without any noticable glitches.
I am keeping turbo off now however, as I do not like its unpredictability.
Here is a screenshot showing BIOS voltage settings. Particularly interesting is the QPI/DRAM as it is right in line with Intel's data sheet that specifies the maximum QPI/DRAM voltage for non-failure conditions. I measured them with a MM however directly on the board and they fall a bit below what is stated here (about 0.02V - 0.03V less). Better cooling and a cooler room (21C ambient) would also yield lower voltages for me, but hey, cheap and chic :p: Also, I could do 181 BCLK to just get that every bit extra, but I like round numbers haha
Outstanding post dejanh!
For curiosities sake, as I'm well aware that everybody's system is different, what are the settings that you are using to achieve your 4.0Ghz?
Thats what you get from a IMC.Quote:
Originally Posted by Nanobot
You just could make a quick and diry excel sheet.;)Quote:
Originally Posted by dejanh
Where exactly do you set the QPI multiplier?
Thanks for all your work.
I take it that your only running 3 sticks? I've got 20x189 using the 2:8 mem multi with 6 sticks stable using the same voltages as the prime I posted. I believe there's no difference between the 920, 940, 965 XE chips other than the multis. Evga released a beta bios that unlocked the other memory multis for the non XE chips.Quote:
Originally Posted by dejanh
interesting observations, mine may just be an exception...
my 20x200 run prime stable 9hrs...
Vtt 1.32, uncore 18x, QPI 36x, mem 8x
vcore 1.33 load, 1.356 bios
ram 1600mhz
Quote:
Originally Posted by Bobbylite
I only have the cpu block in my loop running a Pa 120.3 with Petra's Yate L oons and some no name red led fans in a push-pull config. I am priming at 4320 with 1.48 volts now temps still good at idle and load.Quote:
Originally Posted by bmilos
It's known as QPI link data rate I think on R2E (speaking from memory). You have to work out the multiplier backwards from the MT/s figure. So if you have a 7200MT/s, that translates to 3.6GHz which with a 200MHz BCLK translates to 18x QPI multiplier.Quote:
Originally Posted by bmilos
Gigabyte takes GT/s as reference so they have a 36/40/44 multi, Asus on the other hand takes the actual clock so its multi 18/20/22.Quote:
Originally Posted by dejanh
Just stay under 8000GT/s / 4000MHz qpi clock and thing should be fine.
200 x 21 is still priming, it's only been 25 minutes, but normally it crashes in like 1-2 minutes, so this is a good sign.Quote:
Originally Posted by dejanh
Mines 36/44/48?Quote:
Originally Posted by Hornet331
Can I ask where the 8:9 ratio comes from?Quote:
Originally Posted by dejanh
From this..Quote:
Originally Posted by Lukee
http://img114.imageshack.us/img114/5838/79439152nt4.jpg
Going by that, by dropping the mem multi along with uncore. Although you could push it to x15 and stay under the described ratio.
http://img75.imageshack.us/img75/2189/51477749le7.jpg
Thanks. Just reinstalled Office and created a spreadsheet like yours.Quote:
Originally Posted by fornowagain
Why won't they give us a QPI multiplier of 40? That would solve things.
40x 16x 8x and we are good to go. On that same note, are they going to open up odd numbered multipliers for memory? It sucks that at 200 Bclk, you only have 1200 - 1600 - 2000 to choose from.
Do you forsee the new bios updates giving us more values so we have more control over the OCs?
Congrats dejanh best enlightning post i have seen in weeks!
Quote:
Originally Posted by Bootsy
What speed are you running your memory?
Are you still priming?
Very interested in a stable 4.3 oc
I finally have 200x21 stable, @ 1.44v(bios), 1.404 CPUz
Funny thing is that my 195 x 21 was stable with 1.35v(bios) AND I can run my memory at 1600 not 1200.
For that extra 105 Mhz, it's costing me 2000 MB/s in Read memory and almost a full .1 more in Vcore. I don't think it's worth it at the present time. What do you guys think?
Yeah, only 3 sticks. 6 should work as well however.Quote:
Originally Posted by safan80
ops, sry i had the wrong numbers in my mind. :p:Quote:
Originally Posted by fornowagain
On my GB board my lowest QPI multi is 36x, other than 'slow mode' which brings the QPI clock to sub-100mhz range. When i choose 36x though i am clearly on 18x because my QPI clock shows as 3.9ghz rather than 7.8ghz. :shrug:
Anyone find raising the IOH core..input/output hub... volts on cpu, has any effect on stable overclocks especially at higher bclk? Was reading last night somewhere, and on one thread on this forum that some were increasing it to get higher bclk? I have not played with it much yet, but I think I had it raised on my 20x200 run, but thought it irrelevant after rerunning my 182x22 run still stable with normal IOH, now not sure if that setting matters or not. Going to play with it on my current settings to see if can lower vcore. Or does anyone have explanation of what it does...all I know it is on cpu, IOH is interconnected via qpi to cpu, and IOH connects to ? pci peripherals?
Volts required to get to 4.2 6hrs prime (blend)= 1.38 and cpu pll to 1.86 all others auto. Haven't pushed her further yet.
Water cooled with 120.3 ambient temp=49F (Michigan basement).
Please explain how this is possible then: http://www.xtremesystems.org/forums/...79&postcount=2Quote:
Originally Posted by dejanh
2Ghz Ram, 4Ghz Uncore but only 2.5ghz QDI speed with 143Mhz BCLK x18 QDI multiplier.
Has anyone else confirmed that QDI has to be faster than Uncore to POST?
Some prime runs on mine have uncore faster than QPI link speed...I am running with uncore faster than QPI now.Quote:
Originally Posted by HKPolice