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Intel Sandy Bridge Overclocking Guide E-mail
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Written by Servando Silva   
Tuesday, 19 April 2011
Table of Contents: Page Index
Intel Sandy Bridge Overclocking Guide
Why Should I Overclock?
Overclocking Applications and Utilities
Processor Stability Testing
Understanding OC Variables
UEFI and Testing Methodology
Overclocking Frequency vs. Voltage
Overclock vs. Power Consumption
Overclock vs. Temperatures
Final Thoughts

Overclock vs. Power Consumption

Some people cry a lot about power consumption (including me). I'm the kind of person who wants the best efficiency if possible, and that means I want my CPU as fast as I can without doubling power consumption. As if we didn't have enough with all the extra components already! Reality is, many people don't even bother about power consumption, and after all, that's why they paid for an 800 watt PSU (even if they normally don't use more than 300 watts). Anyway, I'll test both Idle and Prime 95 modes and measure CPU power consumption with Real Temp 3.67. Have a look at the next results as they represent power consumption in idle mode. These numbers are important as you probably keep your PC near idle mode 70% (or more) of your time.


Woah! Those processors barely use 6 watts at idle mode. This is with EIST and Turbo Boost enabled. When overclocked, it seems the CPU power consumption raised somewhere between 10 and 11 watts, but still, seems like a very nice result. Anyway, we can only make conclusions after analyzing Full Load results, but I hope they won't increase that much. Let's have a look at the next chart:


OK now we're talking. The Core i7 2600K consumes 10 extra watts against the Core i5 2500K at full load. When overclocked to 4GHz, the i5 increased 16 watts while the i7 increased 17 watts. The next step was overclocking both CPUs at 4.4GHz which according to the voltage it needs; it seems like the sweet point for Sandy Bridge overclocking. The Core i5 increased its power consumption to 82 watts, which is 23 extra watts against stock values, while the i7 increased to 94 watts, nearly arriving to the TDP.

Finally at 4.8GHz the Core i5 consumes 90 watts, which is 50% extra consumption, while the Core i7 2600K reaches 105 watts, representing a 50% extra power consumption also. Of course, increasing power consumption means the CPU heatsink will have more watts to dissipate, thus increasing CPU temperatures. Let's have a look at our voltage vs. temperature results in the next page then.



# RE: Intel Sandy Bridge Overclocking GuideJackNaylorPE 2011-04-21 12:37
Would have liked to see a comparison of setting the Turbo / Voltage to a fixed number versus using the Max turbo frequency / voltage offset method.
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# RE: RE: Intel Sandy Bridge Overclocking GuideServando Silva 2011-04-21 13:53
Hi Jack. Please check our forum as I've just explained why I didn't test that way. It would need another article just for that, or at least, a new set of tests.
Take care.
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# RE: Intel Sandy Bridge Overclocking GuideRobert17 2011-04-21 13:24
Nicely done. But you did make it seem like the "good old days" of mounting a PVC tank with a fish-tank pump feeding from an ice chest full of frigid water may be a thing of the past.

Not to get too far away from your core article regarding Sandy Bridge, but do you have any insight as to whether or not AMD will maintain OC potential in their new lineup?
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# RE: RE: Intel Sandy Bridge Overclocking GuideServando Silva 2011-04-21 13:57
Yeah. I've been overclocking for the last 10 years and I know many others who have been doing it for 15 years or so.
You know that phrase: "Like the old days". I'm not saying I don't like this new way of overclocking. Actually, I like not to pass several hours to find such a nasty or complex configuration for my PC, and doing it the the old way. New OC tools and features help a lot when what you just need is to bump your PC speed and get back to work, but sometimes it was funny to test and read a lot for that.
Also, sub-zero overclocking is quite fun, but with Sandy Bridge they somehow killed it.

Regarding the new AMD processors, I still have no information about them, so I'm anxious to test one.
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# RE: RE: RE: Intel Sandy Bridge Overclocking GuideDavid Ramsey 2011-04-21 14:30
The new way of overclocking-- raising the maximum multiplier use by Turbo Boost-- has one huge advantage over the old ways of increasing BCLK or the base multiplier: to wit, the processor can still downclock to low speeds when you don't need the performance. My 4.1gHz 980x always runs at 4.1gHz. A 4+gHz Sandy Bridge can idle at the same speed it does non-overclocked, saving a lot of power (and generating less heat).
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# RE: RE: RE: RE: Intel Sandy Bridge Overclocking GuideRobert17 2011-04-21 15:51
I'm not complaining. Maybe just pining a bit. I set up a simple OC on my MB, seldom vary it due to the stability, change to game, pretty much ignoring the power consumption. My bad. What limited understanding I have of UEFI seems to indicate that rebooting to change configs may become simpler.

And certainly the advantages of having a MB/CPU combo that is "self-monitoring" power, thrust, pitch and yaw outweigh the "good old days". And yes, I mostly like automatic transmissions over three-on-the-tree these days as well.
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# RE: RE: RE: RE: Intel Sandy Bridge Overclocking GuideServando Silva 2011-04-22 11:45
Completely true! As I've said. I'm not really complaining. I like the new way as it benefits final users. It's just they took away that "chilli spice" when overclocking. Also, they limited it to Unlocked processors and certain platforms.
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# RE: RE: RE: Intel Sandy Bridge Overclocking GuideOlle P 2011-04-22 10:30
"... sub-zero overclocking is quite fun, but with Sandy Bridge they somehow killed it."

You can say that again! I read somewhere that Sandy Bridge reach its peak performance at about 20C. If you cool it more than that it won't reach quite as high speeds.
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# RE: RE: RE: RE: Intel Sandy Bridge Overclocking GuideServando Silva 2011-04-22 11:48
Do you want me to say it louder? Yeah!
I've heard some processors do worst when going below 10-20C degrees. Again, it's good because now many users will be able to play and overclock without going extreme, but it won't be as interesting for extreme users.
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# RE: Intel Sandy Bridge Overclocking GuideJackNaylorPE 2011-04-24 15:35
One other thing I'd love to see addressed ... POITA ain't I :) ..... the 2600k I assume is running hotter cause of the HT..... Prior to reading the article, I cam to the same conclusion that 4.4 Ghz was the sweet spot for the 2600k for 24/7/365. Since this was a B'day build for Son No. 3, w/ Spring break and all I haven't been able to get near the thing in a week.....I used the Asus BIOS Profile feature to store OC Profiles from 4.0 to 4.8 GHz w/ these temps on the SIlver Arrow cooler:

Max Core Temps under (Idle - P95 load)

GHz..... 3.8 ... 4.00 ...... 4.2 ........ 4.4 ........ 4.6 ....... 4.80
Core 1 (51) (31 - 52) (29 - 54) (29 - 56) (31 - 62) (29 - 69)
Core 2 (53) (30 - 54) (30 - 56) (30 - 60) (31 - 66) (28 - 75)
Core 3 (53) (23 - 55) (22 - 57) (22 - 60) (31 - 68) (28 - 79)
Core 4 (51) (29 - 52) (28 - 55) (29 - 57) )31 - 65) (28 - 72)

Hope that formats well

What I am thinking now is making a "gaming profile" w/ HT turned off since I can prolly drop 7 - 10C at 4.8 Ghz ..... will give it a # when kid gets back in school but wondering if anyone's tried yet on SB.
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