Intel's Core i7 870 & i5 750, Lynnfield: Harder, Better, Faster Stronger
by Anand Lal Shimpi on September 8, 2009 12:00 AM EST- Posted in
- CPUs
Overclocking: Great When Overvolted, Otherwise...
Back when I asked Intel why anyone would opt for LGA-1366 over LGA-1156 one of the responses I got was: overclocking. The most overclockable CPUs will be LGA-1366 chips.
We tried overclocking three different CPUs: the Core i7 870, Core i7 860 and Core i5 750. We overclocked using two different coolers: the retail low profile HSF and a Thermalright MUX-120 (the heatsink Intel is sending around to reviewers for high performance testing). I'll get one thing out of the way: the retail heatsink pretty much sucks for overclocking:
| Intel Core i7 870 | Max Overclock (Turbo Disabled) |
| Intel Retail LGA-1156 Cooler | 3.52GHz (160MHz x 22.0) |
| Thermalright MUX-120 | 4.20GHz (200MHz x 21.0) |
The Thermalright enables higher overclocks by removing heat quickly enough allowing us to increase the voltage to the CPU. While roughly 1.35V is the limit for the retail cooler, The Thermalright MUX-120 let us go up to 1.40V. In both cases you need to have a well ventilated case.
Um, yeah.
Now for the actual overclocking results. We overclocked in two ways: 1) with turbo mode enabled and ensuring stability at all turbo frequencies (both single and multiple cores active), and 2) with turbo mode disabled simply going for highest clock speed.
The results are in the table below:
| CPU | Stock Clock Speed | Max Overclock (Turbo Enabled) | Max Overclock (Turbo Disabled) |
| Intel Core i7 870 | 2.93GHz | Default: 3.39GHz (154 x 22.0) 3C/4C Active: 3.70GHz | 4.20GHz (200 x 21.0) |
| Intel Core i7 860 | 2.80GHz | 3.23GHz (154 x 21.0) 3C/4C Active: 3.54GHz | 3.99GHz (210 x 19.0) |
| Intel Core i5 750 | 2.66GHz | 3.2GHz (160 x 20.0) 3C/4C Active: 3.96GHz | 3.92GHz (206.5 x 19) |
For best performance with all four cores active, disabling turbo mode is the way to go. Otherwise you have to reduce the BCLK in order to make sure your system is still stable when the one-active-core turbo mode kicks in. For example, with our Core i7 870 with turbo disabled we hit 4.2GHz using a 200MHz BCLK. If we used the same BCLK but left turbo enabled, when only one core was active we'd hit 5.4GHz - clearly not realistic with only air cooling.
The benefit of leaving turbo enabled is that you get a more balanced system that's not always using more power than it needs to.
The Core i5 750
Our Core i7 860 sample wasn't that great of an overclocker
Breaking 4.2GHz with our Core i7 870
At roughly 4GHz overclocks for all of these CPUs, it's reasonable to say that they are good overclockers. But how about with no additional voltage and the retail heatsink?
| CPU | Stock Clock Speed | Max Overclock, Turbo Disabled (No Additional Voltage) |
| Intel Core i7 870 | 2.93GHz | 3.37GHz (22 x 153MHz) |
The stock overclocks just plain suck on Lynnfield, you need added voltage to overclock the chip. With more voltage it works just like a Bloomfield or Phenom II, but at stock voltages Lynnfield just doesn't clock very high. And it has nothing to do with yields.
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goinginstyle - Thursday, September 10, 2009 - link
What is worthless here is your continued ramblings about subjects you have no actual knowledge of right now. Do you own a P55 system? If so, let's see an article from you. Really, you come over spouting off and calling everyone idiots, yet, you we do not see any articles from you at Toms about the subject matter. In fact, we do not see any comments from you anywhere else about P55. Toms, Tech Report, and AT all came to the same conclusion, presented the same type of information (although AT discussed subjects like PCIE), and yet you do not comment on those other websites.Either you are posting here because you think your negative posts will somehow get you attention that your mother never gave you or you are doing to try and look important to the people in charge at Toms. I hope to God that they never allow you to post another piece of garbage on their site. Really, that article was a straight copy and paste from several other articles on the subject along with Wikipedia information. I am surprised you were not sued for plagiarism, maybe you were and that is why you are over here.
So far, all of your ramblings have only proved your total lack of intelligence when it comes to computer components. Once again, when will we see you making comments on Toms about their similar coverage or when can you expect to see your expert PP article on the site?
eternalfantasy - Tuesday, September 8, 2009 - link
Fully agree up to the AMD part. This is the most biased review I've seen published by Anandtech to date. I think a "Buy me now!" link at the end of the article with an Intel sponsored Ad will complete the article perfectly.Stock clock speed CPU review is what highstreet mags for average Joes write about. Excluding what's importent for readers of tech sites, such as:
Clock for clock comparison
Maximum overclock with similer priced CPU/platform
is just blatent attempt at glorifying Intel's mainstream platform to look like more then what it really is. A cheaper mainstream alternative to the X58 that has been avaliable over a year ago.
PassingBy - Tuesday, September 8, 2009 - link
As released, Core i5 and 1156 Core i7 have no IGP market, so presumably people reading this review will have no interest in using an IGP.In any case, we can safely say that your prognostications like 'a brain dead platform for brain dead people' were total bullshit, as many people tried to tell you. Now, many more people can place a Nehalem-based system on their list of possible purchases. Clarkdale will extend Nehalem/Westmere to even lower price points (and yes, then you can start comparing IGPs, if you like).
TA152H - Tuesday, September 8, 2009 - link
You're really confused.Honestly, anyone who knows anything about computers would be pretty stupid to get this platform. It's fine stock, but when you throw in overclock, the i7 920 is the better choice.
But, here's your hypocrisy. This article was main for mainstream people, since there's no overclocking comparisons, really. The IGP is what makes AMD work, and they do sell their processors into this market. Anand was commenting on how AMD had to lower their prices, so within this context the entire market is applicable. You didn't understand the context, did you?
I didn't say the platform was brain-dead, although you seem to be. I said it was brain-damaged. It's a Celeron. If you look at the reviews from better sites, you can see the Bloomfield running at the same speed is faster than the brain-damaged Lynnfield. Anand really tried to obfuscate this, by using bad comparisons or those meant to show the Lynnfield in the best light, instead of just presenting the most useful information. He fooled you, because you're a moron, but not everyone.
I do like this site, or I did, but I'm really getting unnerved by the way they test to show what they want to show, instead of test and then make up their minds. It's really problematic, and it's going to bite them when more people figure this out.
imperialsoren - Tuesday, September 8, 2009 - link
You have a nasty way of conversing.IdolObserver - Wednesday, September 9, 2009 - link
It's not only his nasty way of conversing. He also doesn't have a clue what he is talking about.Zymon - Tuesday, September 8, 2009 - link
I agree in the main part - there are many aspects which seem to have been completely ignored in this, and many other reviews of Lynnfield.It seems strange that you haven't used a level playing field between compared systems: ALL 3 platforms can use DDR3 - you've used X48 for Core 2 chips, but apparently used different RAM than i5. Why on earth have you used an AM2+ board and DDR2 ram for AMD? I guess it's *only* been 9 months since AM3 became available?
As mentioned, a true clock-for-clock comparison would be VERY interesting, using the same RAM, at the same speeds and timings between platforms.
Anand Lal Shimpi - Tuesday, September 8, 2009 - link
Sorry if this wasn't made clear in the review but the Phenom II X4 965 BE used the same test platform as our review of that CPU: an AM3 motherboard with DDR3 memory.I'm out of the office now but I'll update the test tables later this evening to reflect this.
Take care,
Anand
Zymon - Tuesday, September 8, 2009 - link
Cheers for the clarification Anand!- It seemed unusual for one of your articles, hence the comment!
Laters..
snakeoil - Tuesday, September 8, 2009 - link
i want to know if those benchmarks were with the turbo enabled, which would be cheating, because that's overclocking.for every benchmark turbo must be disabled to be fair.
readers are not stupid.