EPTThe Haswell overclocking thread - Page 2
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Cyro
United Kingdom20340 Posts
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Cyro
United Kingdom20340 Posts
![[image loading]](http://i.imgur.com/Ayt8Ukw.png) As a slight update to this i 0x0124 bluescreened while writing post, put system agent to +0.165v, 0x0124'd while on windows load screen, so put it to +0.18v and doing extended testing soon. Default values might be different for different boards, and i'm sure different CPU's will like different amounts of everything. VRIN, system agent, and i hear analog+digital IO can all have large effects on the vcore you need to be stable, or if you are stable at all at a certain overclock - I've failed 4.5 at 1.21vcore before but i'm seemingly comfortably below 1.16 now which is not a small gap. I had a LOT of trouble stabilizing 4.6 without really big vcore increases, and new knowledge+understanding will probably make it easier The more i come to understand Haswell, the more it seems like first impressions of myself and pretty much everybody else were wrong. | ||
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iTzSnypah
United States1738 Posts
From IDF ![[image loading]](http://images.anandtech.com/reviews/tradeshows/IDF/2005/Fall/Day3/Keynote/coarse.jpg) ![[image loading]](http://images.anandtech.com/reviews/tradeshows/IDF/2005/Fall/Day3/Keynote/fine.jpg) | ||
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Ropid
Germany3557 Posts
When the CPU works on different instructions, it will use more or less parts of the core in processing those instructions. Resistance will change depending on how much of the core is used. If you keep the supplied power constant, this means the voltage drops. See here: http://en.wikipedia.org/wiki/Ohm#Power_as_a_function_of_resistance The outside of the CPU will notice the voltage changing, and will react to that by increasing or decreasing the supplied current. The voltage regulator modules (VRM) have to do the things shown in the slide even for completely normal operation. Voltage has to be kept inside the range where the transistors inside the CPU work correctly. I think the slide is about comparing the integrated VRM of Haswell to old external VRM on the motherboard. It also might not be a comparison with actual motherboards for Ivy Bridge etc., but a comparison with Intel's specification for minimum requirements that might be used in the worst possible motherboards. | ||
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Myrmidon
United States9452 Posts
I don't know much about semiconductor devices, but I'd suggest not even thinking about it in terms of resistance. The behavior of the load is very much not Ohmic (resistive), linear. When you're loading up more processing resources of the CPU, that's causing more transistors to have to switch (wasting more charge stored on gates) as logic gates switch states and more current to flow (more resistive losses in those flows) to make those changes. The voltage regulators are buck converters, so they're switching, not linear either. | ||
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Ropid
Germany3557 Posts
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Cyro
United Kingdom20340 Posts
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Ropid
Germany3557 Posts
The amount of that increase in voltage was still always smaller than what a stress test at the next higher multiplier needed. This means if IBT ran for ten minutes at x47 multiplier, the settings used were definitely stable at x46. Perhaps try that if you are a little tired and feel somewhat desperate. Play with stress tests on the next higher multiplier, then use those settings for your current multiplier. | ||
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Cyro
United Kingdom20340 Posts
Perhaps try that if you are a little tired and feel somewhat desperate. Play with stress tests on the next higher multiplier, then use those settings for your current multiplier. I just slept a ton man. I have weeks, months to tune these overclocks, but i need to understand. I've had 45x@1.158 be fine for 3 hours (stress test lightly, then gaming) but i've also had 46x fail at 1.26. It would be ridiculous to overvolt vcore by more than 0.1v just for stability. Actually it seems like the CPU doesnt give a damn what my vcore is, it'll fail anyway, which i need to fix.I mean it baffles me that i can run IBT for 40 minutes and browse/game for a couple hours again - and then reboot, and fail IBT in 30 seconds with identical settings, reboot again, crash opening firefox, reboot again, down in less than 20 seconds, like damn, what am i doing so seriously wrong? | ||
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Ropid
Germany3557 Posts
It was only short tests, I think, but I have this recorded: IBT: 4.6ghz -> 1.215v 4.7ghz -> 1.265v 4.8ghz -> 1.320v I'm actually running 4.6 GHz at 1.255 V now. At 1.250 V, WHEA warnings show up in the Windows event log. Those tests I did, that's really not very stable. I didn't actually record the failures. I just recorded that it has a good chance to pass ten runs of IBT at 1024 MB memory use (or something like that). | ||
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Cyro
United Kingdom20340 Posts
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Alryk
United States2718 Posts
4.4Ghz 44 Multiplier, 100 BCLK @ 1.14V 4.0Ghz Uncore/Cache @ 1.12V +.15V Digital, System, and Analog IO voltage 1.85VRIN 4.5 Ghz 45 Multiplier, 100 BCLK @ 1.18V 4.0 Ghz Uncore/Cache @ 1.12V +.15V Digital, System, and Analog IO voltage 1.85 VRIN Max temps at 4.4: 82, 79, 76, 72 Max temps at 4.5: 89, 87, 84, 80 Less toasty, but still toasty. Failed 4.5Ghz all settings the same as above but at 1.16V. IBT failed on me, although I didn't BSOD or get any freeze ups. 4.5Ghz at 1.17V, all the same. Same as above - IBT failed me but didn't BSOD or lock up. Testing 1.175V 4.5Ghz at 1.175V failed. See above I haven't tuned 4.5 yet, while I'm pretty sure 4.4 can't get any lower, I've tried a lot of combinations (mostly from Cyro's suggestions, I've ruled out other things as well. Lower VRIN works much better for me). On the other hand I'll see how low I can get 4.5, and I'll probably test different BCLK's today as well. Edit 1: 1.18V passed compared to 1.2 original Edit 2: Failed IBT at 1.16V Edit 3: Failed IBT at 1.17V, no lockup or BSOD (on fourth test of Very high (4096MB) test) Edit 4: 1.175V fails on the 5th Very High test. Seems like 1.18V is my stable point. | ||
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Catch]22
Sweden2683 Posts
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Alryk
United States2718 Posts
Edit above: 1.18V passed at 4.5 Ghz. I'm really surprised as to how close it is to 4.4, I really couldn't seem to get 4.4 any lower. | ||
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Catch]22
Sweden2683 Posts
On June 16 2013 03:00 Alryk wrote: 90 celsius stress testing is probably fine. I hit 90 stress testing but SC2 doesn't go over 55 celsius. Stress testing puts an unnecessary amount of temperature when it's using AVX it seems. For example x264 and IBT will both put you at 100% load, but IBT will be 25 celsius hotter when you have AVX on. Edit above: 1.18V passed at 4.5 Ghz. I'm really surprised as to how close it is to 4.4, I really couldn't seem to get 4.4 any lower. Ah, thanks, and for later idle and load just when playing games? | ||
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Alryk
United States2718 Posts
Edit 3 above: 1.17V also canceled IBT on me. No lockup. Testing 1.175V! Edit 4: 1.175V fails on the 5th Very High test. Seems like 1.18V is my stable point. | ||
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Cyro
United Kingdom20340 Posts
I'l get this sc2 benchmark with uncore down at stock (gotta try it multiple times, cause sc2 likes to stutter which throws off average fps a bit and records minimum fps as 0 instead of your actual minimum) and then post where i am at | ||
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CptCutter
United Kingdom370 Posts
Im currently running (what i pressume is stable even though prime95 forces it to high 80's low 90's and caused it to crash 19minutes which i dont actually think was because of the 100c ceiling) 4.4ghz with 1.216v (as far as i can tell is excessive and have not tried pushing it down yet). only messed with multiplier since im new to overclocking and manually setting voltage (the auto sets the voltage at 1.3v+ with 4.2ghz 0.o) Also, the 1.3v+ ran for around 18minutes before i cancelled the prime95 due to it hitting 95c. I could try with other similar settings, but i will probably just look at seeing either how far i can push the overclock on this voltage, or how far i can drop the voltage with this overclock. I also left the thermal paste that comes with the h100i on instead of using the artic silver 5 that i bought, but i will be removing it soon when i get some cleaning stuff to see if the artic silver is better. | ||
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Cyro
United Kingdom20340 Posts
Do you have i5 or i7? Is this with AVX on or off?* *You can check by running IBT, avx off should give you ~65gflops at 4.5ghz (or a bit more/less depending on ram etc or other things using cpu) and avx on will give like twice as high. | ||
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Cyro
United Kingdom20340 Posts
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