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Core i7-870 Overclocking And Fixing Blown P55-Based Boards

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Our motherboard roundups have shown that Intel’s LGA 1156 interface brought with it a greatly needed modicum of efficiency compared to the enthusiast-oriented LGA 1366 platform. But only part of that power savings comes directly from the Lynnfield-generation CPU core, with remaining reductions found by eliminating all remaining northbridge functionality from the chipset and reducing it to a single component. Furthermore, much of the power savings that the new CPU core provides comes from slight refinements that have allowed the new processors to operate at a slightly lower voltage, a characteristic that’s typically disregarded when overclocking.

Using the same 8MB L3 cache and 45nm die process, the 37% difference in thermal design power (TDP) between Bloomfield- and Lynnfield-based processors is only realistic when both are left at their respective stock settings. Forcing both processors to identical core voltage levels for the purpose of overclocking causes the newer part to take on much of the previous part's inefficiency, a fact revealed only through extensive testing.

Thus, when some manufacturers economized the voltage regulators of “overclocking-friendly” LGA 1156 motherboards by what their engineers thought should be an acceptable level, they were shocked to learn that these parts couldn’t stand up even to our moderate overclocking tests. The results are documented in our subsequent test of $100-$150 P55-based motherboards.

A 150W board limit certainly sounds generous enough, but our testing has proven that it’s very easy to exceed that limit even at the moderate voltage levels supported by CPU air cooling. We begin today’s investigation with a power analysis, using a board known for its solid overclocking capability, before moving on to examine how the manufacturers of two previously-failed motherboards have addressed their problems.

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cyberkuberiah 11/03/2009 6:19 AM
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but some of us would rather give some extra beans and go 920 , and have dual pcie2.0 x16 . a few extra watts doesn't matter too .

anonymous 11/03/2009 7:02 AM
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FYI: Power consumption of switching cmos silicon increases with the square of voltage, and linear with frequency. The increases shown here seem to be in line with that, rather than the stated decrease in voltage regulator efficiency (which certainly does decrease, but probably much less).

Crashman 11/03/2009 8:01 AM
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jeffunit 11/03/2009 11:32 AM
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bucifer 11/03/2009 11:50 AM
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I would be great to see how the more popular i7 860 or at least i5 750 scale with the voltage.
I don't think i7 870 is a popular choice because of it's price (people would go for socket 1336)

ctbaars 11/03/2009 12:32 PM
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Thanks for article.
For me - This and previous articles have convinced me to game at stock, w/ tb+ settings on, and a high end GPU card and the i5 is most appropriate for my usage. I need to condition myself to turn off the computer esp. when noone is home.

avatar_raq 11/03/2009 2:40 PM
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Although Thomas labels Asrock as "succeeds" I will not buy their motherboards, you'll never know what else this company ignores in the bios, and do you think they would fix that issue if it weren't for THG? After how many failing boards?

tecmo34 11/03/2009 2:52 PM
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cyberkuberiah :
but some of us would rather give some extra beans and go 920 , and have dual pcie2.0 x16 . a few extra watts doesn't matter too .


I agree with you 110%... :D

Also, I would like to see the voltage scaling using the i5 750, as mentioned by bucifer

Onus 11/03/2009 3:10 PM
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A few extra watts being "used" is fine. A few extra watts being "wasted" is something else entirely.
I don't see a howling difference on these overclocks either. If I bought an i7, that probably means I'd have little reason to OC it.

While ASRock seems to be taking a "successive approximations" approach to improving their products, the ones I've bought so far have all been solid, but any OC has been mild.
And, once again (even if it isn't quite epic), MSI = FAIL.

jerreece 11/03/2009 3:49 PM
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I was glad to see this article. I was just thinking about this whole debacle this morning. :)

anonymous 11/03/2009 3:54 PM
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"The result of huge power losses with moderate performance gains is a decrease in efficiency of over one third at our highest settings"

The first thing i care about when over clocking is being "green"
Why is this even in the report?

Crashman 11/03/2009 4:02 PM
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Antigreen :
"The result of huge power losses with moderate performance gains is a decrease in efficiency of over one third at our highest settings"The first thing i care about when over clocking is being "green" Why is this even in the report?



Sometimes you can acgtually gain efficiency when overclocking: This is especially true when voltage levels aren't altered.

cyberkuberiah 11/03/2009 4:53 PM
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avatar_raq :
Although Thomas labels Asrock as "succeeds" I will not buy their motherboards, you'll never know what else this company ignores in the bios, and do you think they would fix that issue if it weren't for THG? After how many failing boards?



i'd go with evga/asus ,and for amd , gigabyte or asus . the crosshair 3 formula is top end at just 200 dollars .

Shadow703793 11/03/2009 6:05 PM
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Can some one please make a list of what motherboards use the problamatic Foxconn socket?

warezme 11/03/2009 6:13 PM
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Whats wrong with 3.8Ghz? Its good overclock, with minimal stress on all your junk. Why folks have to push their stuff to 4Ghz or higher stressing the hell out of the hardware just for a couple more lousy FPS. I have an X58 that can push voltage and run at 4.2Ghz but voltage and heat requirements go up way to much and only give me a few more FPS. Its not really worth it.

grimjester 11/03/2009 6:55 PM
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Crashman :
Can you turn that into a more accurate estimate than 200W to 240W, where all that can be proven is that it's "high, but less than 240W"?



I'm not sure how to interpret the results, but the best fit I get for trying to get a constant W / (GHz * V^2) is a base load of only 7W plus a draw of 36.63-36.72W * frequency in GHz * voltage squared. The fit is fairly accurate; there's a 0,26% difference between the min and the max.

Obviously stuff other than the CPU draws more than 7W, but I don't know enough about the hardware to give an explanation. I'd assume that you get fairly close to 7W + (voltage^2 * GHz * 36,7W) if you measure the draw at other speeds and voltages though.

Proximon 11/03/2009 7:21 PM
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Thanks Crashman, this goes towards a resolution and at least we have a few lower budget boards now that look to be relatively safe.

Didn't you use a different PSU last time? Playing it safe with the higher quality 850HX maybe?

Crashman 11/03/2009 7:21 PM
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Shadow703793 :
Can some one please make a list of what motherboards use the problamatic Foxconn socket?



ASRock, Asus, Biostar, ECS, Foxconn, Gigabyte, and MSI use Foxconn sockets. Jetway and EVGA use the cheaper Lotes sockets.

Crashman 11/03/2009 7:38 PM
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warezme :
Whats wrong with 3.8Ghz? Its good overclock, with minimal stress on all your junk. Why folks have to push their stuff to 4Ghz or higher stressing the hell out of the hardware just for a couple more lousy FPS. I have an X58 that can push voltage and run at 4.2Ghz but voltage and heat requirements go up way to much and only give me a few more FPS. Its not really worth it.



Uh, d00d, let me see if I can explain this in terms you can understand: 1.45V has been used for 45nm Intel processors long enough that it's now a standardized OC test voltage. There are many reasons for it having become this standardized test voltage, including the fact that it's considered the maximum safe voltage in some Intel documentation, that it's the maximum voltage most processors can run using above-ambient cooling, that it's the spot just before power consumption spikes, etc. It makes sense, and because it's NOT extreme, was never extreme, was never intended to be extreme, and is in no way extreme, it's something that any overclocking motherboard should tollerate.

We understand that cheap boards exist. If you're going to market a cheap board towards low-cost overclocking, you need to put in over-current protection. If you're going to market an even cheaper board with no protection, you need to disable the overclocking features.

It's one way or the other, when it comes to overclocking either do it right or don't do it at all. Half-fast solutions aren't acceptable in the overclocking market. It's a quality issue, and Tom's Hardware has tested MANY high-quality budget parts in the past.

There's no excuse to cut quality when you can instead cut features to produce a cheap product. IE, if you really really really wanted to make a board that could only do 1.35V before blowing the VRM, and really wanted to sell it without overcurrent protection, you'd really really really want to limit the BIOS settings to 1.35V. Because when you didn't, you'd get caught with your pants down by a site such as this one.

To not report such a finding would be proof of a lack of integrity. To give up testing at this setting would be to cave in for low-quality products at the expense of not revealing the superiority of high-quality products. The reader isn't served, the industry is disserviced, everyone loses.


Proximon :
Thanks Crashman, this goes towards a resolution and at least we have a few lower budget boards now that look to be relatively safe.Didn't you use a different PSU last time? Playing it safe with the higher quality 850HX maybe?



Nah, same power supply since September, might have forgotten to change the model in the setup table.

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