Last week Intel introduced its highly anticipated Lynnfield processors under the Core i5 and Core i7 brands. Three chips emerged:
| Processor | Clock Speed | Cores / Threads | Maximum Single Core Turbo Frequency | TDP | Price |
| Intel Core i7-975 Extreme | 3.33GHz | 4 / 8 | 3.60GHz | 130W | $999 |
| Intel Core i7 965 Extreme | 3.20GHz | 4 / 8 | 3.46GHz | 130W | $999 |
| Intel Core i7 940 | 2.93GHz | 4 / 8 | 3.20GHz | 130W | $562 |
| Intel Core i7 920 | 2.66GHz | 4 / 8 | 2.93GHz | 130W | $284 |
| Intel Core i7 870 | 2.93GHz | 4 / 8 | 3.60GHz | 95W | $562 |
| Intel Core i7 860 | 2.80GHz | 4 / 8 | 3.46GHz | 95W | $284 |
| Intel Core i5 750 | 2.66GHz | 4 / 4 | 3.20GHz | 95W | $196 |
We tested exclusively with the Core i7 870 and the Core i5 750, the 860 didn't arrive in my lab until after the review went live. I was spending the greater part of a week with AMD at that time and didn't get to testing until this past weekend. Here's the chip:
What makes the Core i7 860 so interesting is that it's priced on par with everybody's favorite Nehalem: the Core i7 920. The 870 has great turbo modes, but it's nearly twice the price of the 860. The Core i5 750 wins in the price department, but it lacks Hyper Threading - part of what makes Nehalem so tasty in the first place. The 860 effectively gives us the best of both worlds, hence the focus on it for today's review.
I had a few mistakes in my original version of this table, but below you can see the turbo modes offered by the 860. They're not quite as nice as the 870, but the chip is also half as expensive. You'll also see that like the 750 you only get a single bin improvement with 3 or 4 cores active, but like the 870 you get 4 and 5 extra speed bins in the dual and single active core situations:
| Max Speed | Stock | 4 Cores Active | 3 Cores Active | 2 Cores Active | 1 Core Active |
| Intel Core i7 870 | 2.93GHz | 3.20GHz | 3.20GHz | 3.46GHz | 3.60GHz |
| Intel Core i7 860 | 2.80GHz | 2.93GHz | 2.93GHz | 3.33GHz | 3.46GHz |
| Intel Core i5 750 | 2.66GHz | 2.80GHz | 2.80GHz | 3.20GHz | 3.20GHz |
I've explained turbo mode in great detail here. In short, Lynnfield's PCU (Power Control Unit) looks at the number of cores active, shuts down those that are inactive, and uses the thermal savings to boost the clock speed of the active cores - all within the operating specs of the processor. Unless you're overclocking, turbo will never compromise system stability in search of greater performance.
| Single Core | Dual Core | Quad Core | Hex Core | |
| TDP |  |  |  |  |
 |  |  |  |
It works very well in practice, particularly with Windows 7. A question that's come up since the initial review is what happens when background tasks kick in. As I mentioned in the "Speed Limits" section of the Lynnfield review, this is something that can prevent turbo from kicking in:
"There's also the issue of background threads running in the OS. Although your foreground app may only use a single thread, there are usually dozens (if not hundreds) of active threads on your system at any time. Just a few of those being scheduled on sleeping cores will wake them up and limit your max turbo frequency (Windows 7 is allegedly better at not doing this)."
One of the features of Windows 7 is that the OS supposedly does a better job of grouping tasks together on a single core to avoid waking up an adjacent core and negating the gains from turbo mode. I'm still working on finding a good way to measure this but from what I've seen initially, Windows 7 tends to do a good job of grouping threads onto one or two cores - meaning we tend to see the 4-bin or 5-bin turbo modes. The other thing to keep in mind is that the processor can turbo up/down faster than the OS can schedule threads, the benefits of turbo are present even while in the middle of executing a task. Remember what dictates turbo is both thermal dissipation and current consumption; the mix of instructions executed varies depending on the task and even during the task, which in turn varies the frequency your core(s) will run at.
The end result is a system that seems to feel more responsive as well as perform better. Of course none of this matters if you're going to be disabling turbo and just overclocking, but I've addressed that scenario in a separate article today :)
And I don't really have a reason for showing this, but I like tables so here's the current quad-core processor landscape:
| Processor | Manufacturing Process | Die Size | Transistor Count | Socket |
| AMD Athlon II X4 | 45nm | 169 mm2 | 300M | AM2+/AM3 |
| AMD Phenom II X4 | 45nm | 258 mm2 | 758M | AM2+/AM3 |
| Intel Core i7 (Bloomfield) | 45nm | 263 mm2 | 731M | LGA-1366 |
| Intel Core i5/i7 (Lynnfield) | 45nm | 296 mm2 | 774M | LGA-1156 |
| Intel Core 2 Quad Q8xxx | 45nm | 164 mm2 | 456M | LGA-775 |
The Test
| Motherboard: | Intel DX58SO (Intel X58) Intel DP55KG (Intel P55) Intel DX48BT2 (Intel X48) Gigabyte GA-MA790FX-UD5P (AMD 790FX) |
| Chipset: | Intel X48 Intel P55 Intel X58 AMD 790FX |
| Chipset Drivers: | Intel 9.1.1.1015 (Intel) AMD Catalyst 8.12 |
| Hard Disk: | Intel X25-M SSD (80GB) |
| Memory: | Qimonda DDR3-1066 4 x 1GB (7-7-7-20) Corsair DDR3-1333 4 x 1GB (7-7-7-20) Patriot Viper DDR3-1333 2 x 2GB (7-7-7-20) |
| Video Card: | eVGA GeForce GTX 280 |
| Video Drivers: | NVIDIA ForceWare 180.43 (Vista64) NVIDIA ForceWare 178.24 (Vista32) |
| Desktop Resolution: | 1920 x 1200 |
| OS: | Windows Vista Ultimate 32-bit (for SYSMark) Windows Vista Ultimate 64-bit |
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vol7ron - Saturday, September 19, 2009 - link
"No one with any knowledge of computers would buy the i7 860. They'd get the real deal, the i7 920." Unfortunately, there are 30W that beg to differ. No one with a sane mind would pass over the 860 so easily.vol7ron - Saturday, September 19, 2009 - link
I want one :) I think the 860 is the sweet spot for price/performancejordanclock - Saturday, September 19, 2009 - link
I'd say the 750 and 860 are both sweet spots, but for different budgets. They both are amazing performers for their price segment. After motherboard prices come down a tad more, there will be a pretty big gap between the 1156 and 1366. I really don't see the 920 lasting much longer in that kind of situation. Even the 940 is a little less attractive because the performance gains for the amount spent are really lacking when you go above the 870.strikeback03 - Monday, September 21, 2009 - link
Has the 940 ever been attractive? Only for those who couldn't or wouldn't OC a 920.the zorro - Saturday, September 19, 2009 - link
this benchmarks were taken with turbo overclocking on, so the lynnfield is overclocked at least 600 mhz, is illegal to say these are stock speed results, and compare with phenom 2 at stock speed.is unfair and biased.
Lonyo - Saturday, September 19, 2009 - link
A new name for snakeoil?These are stock results in terms of this is how the processor comes as stock - with turbo enabled.
If they were overclocking the CPU outside of what is warrantied and allowed by Intel, THEN it would be unfair, but if the CPU is sold with the capability available and enabled to overclock itself, then it is not cheating or "illegal" to say that it's stock.
If you really want to be amused, then feel free to go back to the 9800XT days of ATI, who are now owned by AMD.
Back in those days, the Radeon 9800XT (made by the now AMD owned ATI) used to overclock itself, from a base clock of 412MHz up to 440MHz if possible.
ATI (now owned by AMD) have already participated in this "illegal" automatic overclocking 'war' and now you say it's biased when Intel use a clever technology to improve performance.
Personally I think it's a great feature, although what should really be done is an examination of its usefulness.
Take some i5/i7 systems, put them in regular cases with stock and aftermarket heatsinks on them, and alter the environment in which they are used to see how good the turbo feature is when it's not a (presumably) open lab environment such as seen at Anandtech.
That sort of suggestion from someone who claims "illegal" benchmark results might be more helpful than claiming it's "illegal" or "unfair".
Is it illegal or unfair to benchmark an ATI card with DX10.1 and an NV card with only DX10 if the DX10.1 codepath in a game does nothing more than improve AA performance? No, it's not, it's taking advantage of a feature that only one side has implemented. To take away from what that side has done would be stupid. Deliberately crippling someone to prevent their potential from being show is stupid. Maybe we should put the best basketball players in wheelchairs so they can't perform as well as normal?
Chlorus - Saturday, September 19, 2009 - link
You kinda wonder when he will realize he's wasting all his time and attention on a frakking computer chip. "illegal"? Illegal with regards to what law?the zorro - Saturday, September 19, 2009 - link
the law that says:you will not steal.
Chlorus - Saturday, September 19, 2009 - link
HOW IS THAT FUCKING STEALING!? How is using a stock feature stealing? You are aware that AMD is planning to use the same feature to?DigitalFreak - Saturday, September 19, 2009 - link
If you guys would just ignore him and not reply to his posts, he'll go away.