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 Post subject: i7 930 Core Voltage advice needed
PostPosted: Tue Mar 16, 2010 10:06 am 
Sharptooth
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I'm a bit puzzled by i7-930 core voltage settings during overclocking. Since I don't know what the stock voltage needs to be I left this setting at Auto in hopes that motherboard knows (Gigabyte X58A-UD3R). But it fluctuates! I didn't know voltage gets adjusted on the fly like multiplier. At stock speed it goes from 0.928 V to 1.248 V. And when I increase BCLK frequency voltage increases by itself. Is this something new to i7-930? I've read various i7 overclocking guides and still confused what should I set voltage to be in the beginning. I want to keep it a low as possible so temps don't go to high. I'd be happy if I can overclock to 3.5 Ghz and keep temps under 77C on 100% load.


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PostPosted: Tue Mar 16, 2010 10:58 am 
Sharptooth
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Just an update. Looks like "Normal" setting (vs. default "Auto") for CPU voltage in BIOS lowered actual core voltage significantly. I'm still unsure why voltage keeps changing :shock:
These are results from setting BCLK to 166, CPU Vcore to "Normal" and QPI/Vtt to 1.315
Idle:
Image
100% Load (it actually goes up to 80C):
Image

Before when CPU Vcore was set to Auto I was getting around 1.37 V constantly for Core Voltate...

P.S. I'm using Cooler master V8 with arctic silver 3 (yes I know 5 is out, but I still had 3 left and there's no expiration date on it ;) )


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PostPosted: Tue Mar 16, 2010 11:28 am 
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I don't have an i7, but you should really consider some new thermal paste. IC Diamond 7 http://www.heatsinkfactory.com/ic-diamo ... 16605.html better than arctic silver 5.


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 Post subject:
PostPosted: Tue Mar 16, 2010 12:07 pm 
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It's normal for the voltage to fluctuate on those boards. It's pretty horrible to watch under load and it's not necessary. I own a X58-DS3R/i7 920 system that does it, and my P55-DS3R/i7 860 system does the same. The default voltages with Intel Turbo Boost Tech enabled gave the CPU around the same or a little more juice at stock speeds than it needed @3.9Ghz. The temps remained the same or a little less too. You'll see how the voltage still increases a little, but it's not nearly as bad. You can see some screenshots if you click on the link below, and I also mentioned how Auto was giving the CPU a "ridiculous amount of juice and making it very hot."

http://www.maximumpc.com/forums/viewtopic.php?t=100135

Load-Line Calibration might help too!


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PostPosted: Tue Mar 16, 2010 4:14 pm 
Sharptooth
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Thanks man! :D Good info! So it's motherboard's fault then... I'm surprised at all I'm not getting BSOD every time voltage automatically drops :) I tried lowering it manually while in windows running Eztune and it crashed right away...


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PostPosted: Tue Mar 16, 2010 9:01 pm 
Million Club [PC]
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Don't use it on auto. Auto is THE WORST voltage setting for overclock. On many boards, auto adjusts voltages to keep it stable. Some boards don't follow the Intel recommended voltages and may increase it automatically if you OC, so you can actually voltage-kill your i7 without ever touching the voltage setting! Here is the i7 930's VID voltage range. .8-1.375V. That voltage range more or less ensures you're in a perfectly safe voltage envelope. What I would do is get it off auto and set it permanently at 1.375V, and then clock it up as much as you can while it stays stable. Once you're at that cap, you can work from there.


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PostPosted: Wed Mar 17, 2010 8:08 am 
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Bratan wrote:
I tried lowering it manually while in windows running Eztune and it crashed right away...
Uninstall the software and use the BIOS! :evil:


It's more stable and GIGABYTE has a ton of features on that board. I enjoy OCing them. :twisted:


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 Post subject:
PostPosted: Sat Mar 20, 2010 1:40 am 
Celeron
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Gigabyte wrote:
Load-Line Calibration might help too!


Mmm.. I'd leave it off. Here's why:

http://www.anandtech.com/cpuchipsets/In ... i=3184&p=6

Quote:
...setting lower voltages with this option enabled actually results in a condition in which the CPU voltage under load is higher than the idle voltage. Imagine our confusion as we desperately struggle to understand why our system is Prime95 stable for days yet continues to crash under absolutely no load. What's more, in spite of the absence of droop and for reasons unknown, enabling this feature artificially raises our CPU's minimum stable core voltage at 4.0GHz from 1.28V to about 1.33V. As a result, our system uses more power under load than is otherwise necessary. Our efforts to reduce our processor's supply voltage backfired - instead of lowering the system's total power consumption we managed to affect a 20W increase.


Also, look at this page, particularly, the first graph:

http://www.anandtech.com/cpuchipsets/In ... i=3184&p=5

It's important to understand that at higher clocks, the CPU is demanding more amps, and thus you'll need less and less (fewer and fewer?) voltage as you'd imagine you would need. Look at the second graph and you'll see that the idle voltage is higher than the load voltage. This is GOOD. You want this. Leave load-line calibration disabled and your overclocks will be nice and stable - on both idle and load.


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 Post subject:
PostPosted: Sat Mar 20, 2010 7:31 am 
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The CPU needs stable voltage too, and that's where Load Line Calibration comes in. Some motherboards are well known to be better/worse than others, and the mileage always varies a little when overclocking. That's why I used the word might. AnandTech was looking at ASUS' implementation with C2Qs. My GIGABYTE P35 boards don't have a LLC option, and they have horrible Vdroop issues. The only way to compensate is to raise the CPU Vcore, or risk a pencil mod. Idle Vcore always looks crazy and it definitely hinders overclocking.

We're working with GIGABYTE's implementation with Core i7 CPUs here, and it's normal for them to be "in a condition in which the CPU voltage under load is higher than the idle voltage." My stock i7 860 Vcore is 1.156 and it was jumping up over 1.3 with Prime95 running. That's with all of the default settings on a P55-DS3R. Manually setting the CPU Vcore and disabling Intel (R) Turbo Boost Tech helps a lot, but we can still see it here (1.312-1.328). LLC is disabled too! My i7 920 does about the same on my X58-DS3R.

Load line droop is an inherent part of Intel's power delivery design. Droop can help to reduce the output-voltage spike that results from fast load/current demand changes.

But in some situations, this will limit users ability to overclock their processor. In the GIGABYTE X58 Series BIOS, users can turn on and off this setting in order to control the load line drooping. This is called Load Line calibration. With this feature turned on, it will automatically fix the processor's vcore droop issue, and ensure the processor receives stable voltage during overclocking.

I trust GIGABYTE a lot more than an old AnandTech article, and I've seen it work. My i7 920 system was having problems F@H 24/7. I spent weeks troubleshooting (mostly voltage settings), and I couldn't figure it out. I decided to enable LLC and all is well. I was able to lower the CPU Vcore too! Now the idle Vcore is less, the load Vcore is about the same, and the system has been running great. LLC isn't something I'm going to enable by default, but it's definitely something I'm going to play with, and pay more attention to in the future.


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 Post subject:
PostPosted: Sat Mar 20, 2010 9:06 pm 
Celeron
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Well said. I think LLC is a matter of trial and error then, if your results were that good. I've had much success with it off, on my Asus, so maybe that's where the difference lies.


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