Power Consumption

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12:00 AM - 09/08/2009 by Chris Angelini

The reduced platform power consumption of the Core i5 and Core i7 CPUs is immediately apparent, even at idle. Both Lynnfield-based designs dip in around 20W underneath the Core 2 Quad Q9550S, which we’ve been using up until this point to replicate the performance of a standard Q9550. The ‘S’ model has a 65W TDP though, so the fact that Core i7-870 and Core i5-750 suck up less juice at idle is impressive. So too is the idle consumption of AMD’s Phenom II X4 965 BE, which also ducks in under the Core 2 Quad.

Fire up the Small FFT test in Prime95, add a FurMark Burn-In test, and the power usage jumps through the roof. Here’s where Intel’s low-power Q9550S shines, turning in the best results. But the two Lynnfields continue to impress with the second and third lowest power consumption figures. AMD’s Phenom II X4 965 comes in fourth, followed by the Core 2 Extreme, and trailed by the 130W Bloomfield-based Core i7-920.

It can be difficult to take thermal design power specs and give them real-world meaning. However, when you do the math, these load numbers make good sense. The TDP of Intel’s low-power Core 2 Quad is 30W below Lynnfield’s spec. Subtract out a power-hungry northbridge and you’re looking at the gap we see here in practice. Add 22W to the X58’s power budget and then take Bloomfield’s 130W ceiling into account; it’s no wonder Core i7-920 sits at the other end of the spectrum.

Talkback
caamsa 09/08/2009 6:37 AM
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Dang! AMD better get their $4iT together. Now I need to decided between i7, i5 or phenom II when I do my next upgrade........technology happens too fast. Looking forward to more reviews on the i5 and mb prices.

Anonymous 09/08/2009 6:49 AM
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People need to be careful when comparing the i7-870 to a i7-920, alot of people pre-release were worried that the 1156 platform was going to dominate the 1366. However when you see the 870 out perform the 920 people need to remember that a 870 is double the price of a 920, and even when you factor in a motherboard a 920 setup comes out cheaper than a 870.

Now the i5 750 on the other hand is great performance at a great price, and would certainly be the budget gamers new weapon of choice.

I currently have an i7-920 setup which is my main rig and am very happy with it and not at all upset to the see the 870 outperform it (since the 870 would cost me twice as much). I also have had an i5 750 setup now for over a week (the 1156 processors and motherboards have been available here in Australia for nearly 2 weeks now) and it is an amazing processor for the price of it.

So what am I trying to say? 1366 is still a good platform for the top end of the market. The i5 are fantastic new processors for their price, and the 1156 i7's are just confusing and I'm not really sure who they are going to appeal to? I could understand it if Intel launched the 1156 i7's in 6months time when alot of users are already using the 1156 platform and are looking to upgrade their CPU without a new mobo. But to anyone looking at getting a 870, just get an 920 and use the extra cash on the mobo and ram to go with it.

Nintendork 09/08/2009 6:56 AM
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A little confusing the charts.

I would prefer a bench with HD4890. They scale better in CF.

aspireonelover 09/08/2009 7:00 AM
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I can tell, I'm gonna fall in love with the i5 processor

cabose369 09/08/2009 7:43 AM
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Intel needs to come up with a simplified naming system for their products. They are as bad as NVIDIA is right now in terms of naming their products.

There is sooo much to learn and there is so much information here.... I feel confused!!

alikum 09/08/2009 7:45 AM
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Well, I just hope that the Core 2 Quads will drop in prices significantly so that I could grab the high-end one for my final LGA775 upgrade!

buzznut 09/08/2009 7:46 AM
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Well this is good news for consumers. I'm not certain why it took so long for Intel to make some mainstream proc like i5, but for intel fans it seems worth the wait.
This will also compel AMD to bring some more value to the market. Nice article.

jawshoeaw 09/08/2009 7:48 AM
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unclewebb 09/08/2009 7:54 AM
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i7 Turbo is a good tool to monitor the multiplier of Core i5/i7 CPUs.

http://www.fileden.com/files/2008/ [...] /Turbo.zip

It uses the method that Intel recommends in their November 2008 Turbo White Paper.

evolve60 09/08/2009 8:36 AM
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"Intel Core i7-920 Extreme (Bloomfield) 2.66 GHz, LGA 1366, 4.8 GT/s QPI, 8 MB L3, Power-savings enabled"

Since when has the I7-920 become an extreme?

Dekasav 09/08/2009 8:36 AM
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jawshoeaw :
damn, 150 watts at idle?? Is that just the cpu? I hope the gaming rigs built on these processors are not left on 24/7. My old AMD X2 3800 system including the monitor uses less than 150 watts at idle (50 of which is the 22" LCD).



The power readings are for the whole system, not just the CPU. And their readings are a bit higher than yours because their video cards are almost certainly more power-hungry than yours, and they have a quad-core cpu, running significantly faster than your dual-core (4 cores at ~3Ghz vs. 2 at ~2Ghz, which SHOULD use more power?)

dragonsprayer 09/08/2009 8:59 AM
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Nice article as always THG rules! Ouch amd!

hey guys some tests done at the same cpu speed would be helpfull! thx!

cangelini 09/08/2009 9:01 AM
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Thanks Dragon--check out the In Theory piece that also went up today. It has i5, i7, i7 LGA1366, Core 2, and Phenom II at 2.8 GHz in a bunch of games!

th_at 09/08/2009 9:02 AM
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Deekay_ :
alot of people pre-release were worried that the 1156 platform was going to dominate the 1366.



Who was "worried"? It would've been AWESOME (although not to expect of Intel) if the lower-price platform would've outperformed the high-end item.

cangelini 09/08/2009 9:02 AM
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evolve60 :
"Intel Core i7-920 Extreme (Bloomfield) 2.66 GHz, LGA 1366, 4.8 GT/s QPI, 8 MB L3, Power-savings enabled"Since when has the I7-920 become an extreme?



Typo--thanks for the catch evolve. Pulled that table from a previous review and missed the Extreme!

dragonsprayer 09/08/2009 9:03 AM
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Also - this address people above too and the article.
When you set up an i7 system you turn off the HT and turn up the speed! Turning off a core might even be an upgrade for some. But i agree, the i5 is really a good plateform the mid-mid high level people and at a lower price.

above - too long for intel? for main stream? you could buy a 8400 and run it 3.8 in any system and it rocks.

people have to learn that overclocking is not what it once was, intel does not build all that into the procesor and chipset for nothing so use it! core 2 is still a good main steam system, abit, no upgrading

Korok 09/08/2009 9:57 AM
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Where is the i7 860?

Great read, by the way
All the mixed rumors were really misleading

Intel_ARK_Dude 09/08/2009 10:14 AM
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FYI: All of the Lynnfield-based parts are here:
http://bit.ly/Lynnfield

And a side-by-side comparison with all the key stats are here:
http://bit.ly/LFDcomparison

bigdaddycool 09/08/2009 10:37 AM
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JeanLuc 09/08/2009 10:38 AM
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The AMD Phenom II X4 965 BE is running at 3.4Ghz.............I can remember only a few years ago AMD bragged about getting 'more work done per cycle' where as Intel responded by increasing the clockrate. It now looks like the tables have completely turned and it's AMD that has to keep increasing the CPU frequency to stay competitive.


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