Overclocking i7 950

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
Hey guys im trying to OC my i7 950 to 4.0Ghz plus. I have it at 3.8 now with a 1.25 vcore and all the rest of the settings at auto and its running stable. Im having difficulties getting it to 4.0Ghz and beyond. Ive read the post on how to OC i7's. I dont know if this is a problem with the motherboard, but Whenever I set the QPI to 175 which is about 4.2Ghz, it wont boot up. Once I save the new bios settings, it turns off like normal and then when it turns back on it just sits there with all the fans at max speed, and the LED post on my mobo says F3 on it. It wont get to the stage were it beeps and starts booting up. Ive even set the voltage to 1.30 and it still acts the same.


EDIT:
I upped the vcore to 1.375 and the QPI PLL vcore to 1.250 and its running small FFT's right now at 84C at 4.2Ghz, the temp seems high but i have D0 stepping i7 and I read that the max for those are 85C. Are there any other settings that I can change to reduce the vcore and QPI vcore to drop the temps?





Specs:
i7 950
EVGA SLI classified
mushkin enhanced redline DDR3 1600Mhz
 

CompuTronix

Intel Master
Moderator
Intel has no such "max" 85c specification for any Core i7 variant. Whatever you read was based upon speculation rather than specification.
No. Reducing Vcore reduces temperatures, however, you haven't mentioned your ambient temperature, or whether you're referring to CPU temperature or Core temperature.

Regardless, your temperatures are into overtemp by at least 12c, because your Vcore is at Intel's "max" limit.

Temperatures and overclocking are all about specifications, so it's very important to be specific. If we're not, then the topic makes about as much sense as comparing apples-to-oranges thermal fruit salad in a blender! :pt1cable: My objective is to assure that enthusiasts understand Intel's specifications, standards and test methods, so they can better decide how to apply and manage their overclocking options.

From Intel's Processor Spec Finder - http://processorfinder.intel.com/List.aspx?ParentRadio=All&ProcFam=3052&SearchKey=

All Core i7 9xx variants:

Vcore Max 1.375v
Tcase Max (CPU temperature) 68c
Tjunction (Core temperature) 73c

From the Core i7 and Core 2 Temperature Guide - http://www.tomshardware.com/forum/221745-29-sticky-core-core-temperature-guide


"Section 1: Introduction

Core i and Core 2 processors have 2 different types of temperature sensors; a CPU case (not computer case) Thermal Diode centered under the Cores, and Digital Thermal Sensors located on each Core. The case Thermal Diode measures Tcase (Temperature case), which is CPU temperature, and the Digital Thermal Sensors measure Tjunction (Temperature junction), which is Core temperature. Since these sensors measure 2 distinct thermal levels, there is a 5c temperature difference between them, which is Tcase to Tjunction Gradient. Core i7’s / i5’s and Core 2 Quad’s have 1 Tcase and 4 Tjunction sensors, while Core 2 Duo's have 1 Tcase and 2 Tjunction sensors ...

... The monitoring utilities provided by motherboard manufacturers monitor CPU temperature, while some popular freeware utilities monitor Core temperatures ... Real Temp ... is recommended for users interested in monitoring Core temperatures only ... SpeedFan monitors Tcase (CPU temperature) and Tjunction (Core temperature) ... "


The Thermal Specification shown in Intel's Processor Spec Finder is Tcase Max (CPU) not Tjunction (Core), which is a very common misconception among most enthusiasts. Since there's a 5c gradient between the CPU sensor and the Core sensors, (shown in the following Intel document) - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf - just add 5c to the value shown in the Spec Finder to determine the corresponding Core temperature, which is 73c for all Core i7 9xx variants.

Intel's second and frequently misunderstood Thermal Specification, Tjunction Max, (100c for all Core i7 9xx variants) applies to overtemp protection such as Throttle and Shutdown, so you don't toast your transistors. As such, any i7 9xx Core temperatures which exceed 73c should be considered "overtemp". Further, when specifications are exceeded, then processor degradation becomes a concern, which is explained in the following AnandTech article - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3251&p=6

Prime95 Small FFT's is the Standard for processor thermal testing, because it's a steady-state 100% workload which yields steady-state temperatures, whereas Blend is a memory cyclic workload which yields fluctuating processor temperatures. Small FFT's will reach 97% thermal saturation within 7 to 8 minutes, so a 10 minute test is adequate. Thermal testing should be conducted as close as possible to 22c (72f) Standard ambient, with case covers removed, the computer clear of any desk enclosures, and all fans at 100% RPM to eliminate cooling variables, and to produce consistent and repeatable results for comparisons. If the Gradient between CPU temperature and "mean" (average) Core temperature is not ~ 5c, then BIOS is incorrectly coded. CPU temperature and Core temperatures can be individually calibrated in SpeedFan by following the Calibrations Section in the Temperature Guide.

OCCT and Burn Test (reminiscent of TAT) use LinPack, which shows thermal signatures that resemble the ups and downs of a bad day on the stock market, and cycle between light workloads, through test segments which spray all processor registers with all one's, (100% thermal load = 115% workload), and can push an overclocked i7 9xx with HT enabled at Vcore Max 1.375, right on past Tcase Max to ring the Tjunction Max bell like a fire alarm! :eek:

Since there are very few applications or games that will spike, let alone sustain processor workloads beyond 70% to 85%, utilities which load all registers with all one's are not representative of real-world computing. While these utilities are certainly very useful for stability testing, they are inappropriate for thermal testing. The 3DMark benches are excellent for stability testing, as are applications for ripping and encoding.

To make sense of CPU temperature and Core temperature, compare them to a 4 cylinder car with 5 temperature guages; 4 of the guages are cyclinder head temperatures (closest to the heat source), and the 5th guage is the overall engine temperature, which is 5c lower than the other guages, and is the temperature guage with which we're all familiar. We know the red zone (hot) for the i7 9xx starts at 68c (Tcase Max) on the engine temp guage and 73c (Tjunction) on the cylinder head temp guages, but if we push the engine too hard and peg all the guages, (95c Tcase overtemp / 100c Tjunction Max) then the engine will throttle down.

If you'd like to learn more about processor temperatures, then just click on the link in my signature.

Hope this helps,

Comp :sol:
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
Ok that makes alot of sense. How are some people getting such high overclocks on air even with high voltages and keeping the temps within a safe range. I have good cooling, Thermaltake Speedo Advantage case with 4 120MM fans 1 140 mm and 2 230mm fans, there all blowing air in the correct direction and a zalman CNPS9900 heatsink. It is cold were I live now, around 60F during the day and 20's to 30's at night. My house is set at 68F.

My CPU at stock settings hits the 60's on small FFT's. I also applied the thermal grease according to the arctic silver website for the i7.

Your quotes above from what I said in the first post. I am referring to CPU temp and I stated above about were my ambient temps are. I am currently looking at buying a new CPU heatsink to reduce the temps. Are there other bios settings I can change to keep my computer stable at 4Ghz, but keep the temp at a safe range. I do understand every CPU is different, but Ide like to try everything before I determine that my CPU just gets hotter than most. It does seem like a big jump in temps from idle to full load. Stock settings it idles in the 20's which is good, and when its at 4Ghz it idles at about 35c and then jumps to 84c full load.

EDIT: this is probably a stupid question, but when I play games and do normal tasks it doesnt really ever go in the 60'c, I ran P95 for an hour on small ffts and it was stable with no errors or warnings. So is it fine to keep it at these settings but just make sure it doesnt go in the 70's? but I still want to try everything to get this stable at these speeds with lower temps.
 

CompuTronix

Intel Master
Moderator
HT disabled allows lower Vcore and temperatures.

* Do you perform any tasks which actually benefit from the additional 4 virtual cores?
68f = 20c.

* Have you checked the intake temperature near your case?
* Vcore 1.375 is your BIOS setting, but have you checked Vcore load during Small FFT's with CPU-Z? EVGA boards don't have the best Vdroop characteristics.

* Which temperature monitoring utility are you using? It's possible that your CPU temperature is indicating too high because it's miscoded in BIOS.

* Have you checked Core temperatures with Real Temp?


Also, while you're testing, make sure that you always run monitoring utilities individually, not simultaneously, as they can interfere with one another.

Comp :sol:
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
I do have HT enabled, I dont even know were the option is to change that. Im not very used to this bios because my comp is only a few weeks old. Before I had an ASUS rampage formula which I was very familiar with the.

All I really do on my comp is normal internet browsing and gaming, I havnt checked the intake temperature. I use the EVGA E-Leet program to moniter the temp and it shows the temo on my mobo, which both show the same thing, the e-leet program also shows core temps. I will check real temp today.

EDIT:

I checked the temps with real temp and it shows the same temps as the e-leet program, I didnt run them together, I just closed one and then quickly opened the other. I have my cpu at 3.8Ghz now at 1.25 vcore and all the other settings at auto and the cores still hit 80c and the cpu is around 70.
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
I found the HT option and disabled it and that dramatically decreased the temps. The CPU is at 57C and the cores range from 66C to 71C on small FFTS, but something is still of because thats way more than 5C difference from the cores and the cpu.

Will there be any difference in performance with HT disabled?
 

CompuTronix

Intel Master
Moderator

When you turn off HT, you have 2 options; either decrease Vcore by ~ 0.075, or increase frequency by ~ 200 Mhz.

Also, if your CPU to Core gradient is > 5c, then your BIOS is miscoded, just as I suspected. Are you running the latest BIOS?


I use HT only for Microsoft Flight Simulator X, which is the most CPU bound title you can run. Frame rate is 85% CPU but only 15% GPU. The difference is quite noticable with HT on, however, I don't do any other gaming, so for all other computing needs, I run with HT off. If I had an extensive ripping and encoding task to perform, then I would turn it on. You'll have to experiment with your games, but if they're primarily GPU bound, then it's likely you won't notice any differences in FPS.
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
I just installed the latest bios and the temps are still the same, about 15 degrees difference between the cpu and cores. I set it to default settings with turbo on, so its running at 3.2Ghz and the cores were at 72C, something is wrong here.

It also sets the vcore to 1.235 on auto with turbo on
 

cory1234

Distinguished
Dec 26, 2005
628
0
19,010

Did try reseating your heatsink? I would recommend backing off that overclock unless you invest in a better heatsink.

Try turning off load-line calibration...might help with temps.
 

CompuTronix

Intel Master
Moderator

This is is why overclockers discourage enthusiasts from using "Auto" settings, because more Vcore is applied than necessary.

From a previous post:


Your 15c spread simply means that the manufacturer didn't get it right, which happens all too often. Since your EVGA monitoring utility probably doesn't allow offset corrections, we can still get your temperatures calibrated by using SpeedFan instead of E-lete.


I wouldn't recommend it. Load-Line Calibration (LLC) is designed to improve Vdroop characteristics, and EVGA doesn't exactly have the tightest Vdroop among competing manufactirers. Tight Vdroop makes achieving a stable overclock less difficult. This can be visualized with "SpeedFan > Charts > Voltages" while at idle, then while running Prime95 Small FFT's.
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
is it better to have vdroop off while finding the best OC and getting it stable? or is it best to keep it on at all times?

I will download speed fan right now

I just installed speed fan, but I dont know how to calibrate the temps to show the correct temps. Im running prime 95 with small FFT's and my cpu is at 3.8Ghz at 1.25 vcore the temps on speed fan range from 58-73 throughout all cores,
 

CompuTronix

Intel Master
Moderator
LLC on at all times, and refer to the Temperature Guide for calibrations. Just click on the link in my signature.

SpeedFan has a learning curve and requires some time to set up, so it's not for the squeamish, but once properly configured, it's sweet! :love:
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
Well im wondering if I have a defective CPU. It can run stable at 3.8Ghz 23 X 160 QPI at 1.25 voltage and everything else on auto. If I just raise the QPI by 10, I cant get a stable overclock. I raised the vcore to 1.300 and the QPI vcore to 1.25 and still get blue screens, some of the blue screens are ones ive never seen before. Not just the normal, secondary clock was not recieved, and the IRQ one.

I also bought a new heatsink with HDT on it and 2 cooling fans, but the temps are about the same as what they were before, even at stock settings.
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
I have vdroop disabled so it wont change, but it is at 1.258 in cpu-z during small FFT's. It just seems to hot for the kind of overclock, and its to hard to get it stable at any higher speeds.
 

CompuTronix

Intel Master
Moderator
BIOS is 1.300 and CPU-Z is 1.258 during Small FFT's ... that's a massive Vdroop of 42 millivolts. Mine is 8 millivolts, which illustrates the difference in the quality of Vcore regulation on the motherboard. If you enable LLC, it will reduce Vdroop and increase stability, as I've already pointed out.
 

csflame4432

Distinguished
Sep 17, 2004
42
0
18,530
My bios is set at 1.25, cpu-z is showing the same voltage as the bios. I meant that when I raise the QPI to 170, I cant get a stable overclock even if I set it to 1.30, thats what I meant. But when I ran prime 95 like you asked, I had it at 3.8Ghz and 1.25 voltage

EDIT:

I changed a few settings, I enabled Vdroop, disabled turbo, and disabled HT. Then I set the QPI to 180 and set the voltage to 1.375 and QPI PLL voltage to 1.250 and its running stable now. I tried to get a higher speed at that voltage, but its not stable

My ram is set at 2:8 and is running at about 1450 mhz. Even though the multiplier is lower than what it can be, it seems like its able to achieve a higher OC like this. Now I just want to get it to about 4.4Ghz so the ram will be back at about 1600Mhz, which is the speed its rated at.

I would also be happy if I can keep it at the speed its at, but then start to OC the ram, but I dont have much experience with overclocking ram

Then as soon as I was typing this after about 30 mins of Prime95 small FFT's I got a blue screen saying system_service_exception
 

pegasus-rtf

Distinguished
Apr 20, 2010
6
0
18,510
I have just assembled an EVGA Classified MB and Core i7 950 in a Thermaltake Armor case with water cooling. It is up and running with Windows 7 64-bit, but I'm waiting for MS Office and some other software before I work with it. It is my intention to overclock to about 3.75 GHz. I'm reading your posts with interest. It got up to 34 C on running Super Pi and stays around 25 C on idle. The water cooling works great and this is my first experience with water cooling. It will be about two weeks before I break funds loose to finish this out and go to overclocking. I do lots of Spech Recognition work.

So what is your status now? Have you gotten u to 4 GHz?