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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has407 - Sunday, September 20, 2009 - link
No, there's nothing "wrong" except maybe your assumptions or math?22x 133MHz = 2.93GHz. That's exactly what an 860 should be at with 4 cores active under full load.
An 870 would idle at 2.93GHz; with 4 cores active and under full load you should see 24x 133MHz = 3.20GHz.
yacoub - Saturday, September 19, 2009 - link
Go learn about TDP.hulu - Saturday, September 19, 2009 - link
" According to the Turbo charts, the slowest Turbo speed is higher than the stock speed. Why is that? "It's not only how many cores you use but also what instructions are being executed that contributes to whether turbo is used.
TemjinGold - Saturday, September 19, 2009 - link
I'm guessing it's because if you turn turbo OFF, it would be 2.66.I'm wondering though, if you need 2 cores on the 860, does it shut off 2 cores and use 2 physical ones or does it shut off 3 cores and use 1 physical plus 1 HT core?
TA152H - Saturday, September 19, 2009 - link
Despite your love affair for this chip, it's a solution in search of a problem.It's clearly inferior to the Bloomfield. Despite running at higher clock speeds, sometimes a lot, it actually loses to the i7 920. Overclock them, and there's just no comparison. The i7 920 is better. No one with any knowledge of computers would buy the i7 860. They'd get the real deal, the i7 920. This pertains even moreso for the i7 870. Basically, the Lynnfield is an idiot's procesesor, except for the i5 750.
If you can't afford a Bloomfield, that's really your best choice. Except, like I mentioned in a previous post, this is a Celeron, without the platform. If they coupled this with an IGP, you'd have something that would sell. The i5 750 is still not without appeal with a discrete card, but, then, most of the market likes IGPs. And if you know something, and have some money, you're not going to get the brain-damaged Lynnfield. You'll get the Bloomfield.
It's not a mystery, really. The mystery is why it would even sell marginally well. I think once they couple it with a decent IGP, it will really take off though. Until then, I think they'll be lucky to settle for mediocrity.
The Athlon stole the show. No one needs a brain-damaged version of a better chip, unless it breaks into a new market with price. Arguably the i5 750 did, kind of. Clearly the Athlon did. I think that's going to generate more real excitement, if less motherboard pictorals.
KoolAidMan1 - Saturday, September 19, 2009 - link
Incorrect, there are already benchmarks out there where the i5 720, i7 870, and i7 920 are all underclocked to 2.66ghz (the speed of the i7 920) and overclocked to 3.2ghz (a very attainable turbo speed by the i7 870 and i5 720). The difference in nearly all gaming benchmarks, using settings that takes the GPU out of the mix as a bottleneck, all at the same clock speeds, are within a very very tight percentage range, at the very most a 10% spread (with Crysis and Far Cry 2 it is closer to a 1% spread).http://www.hardocp.com/article/2009/09/07/intel_ly...">http://www.hardocp.com/article/2009/09/...ntel_lyn...
I think the lower price of motherboards makes the LGA 1156 CPUs very very attractive. I don't see any reason to get an LGA 1366 board unless you really want to futureproof yourself for six and eight core CPUs. That said, I don't see a point; most games still use single, maybe dual cores, and upgrading CPUs within a motherboard cycle almost never happens for me. By the time it is time to put together a new PC (average every two years for me) there is an entirely new ecosystem of CPUs, motherboards, and RAM that I need to get into and I end up keeping almost nothing from the old rig.
So yeah, I don't really agree with you.
chrnochime - Saturday, September 19, 2009 - link
Wouldn't it serve you better by creating your own website, instead of attacking Anand's articles and playing second fiddle here? You seem to think you know better than Anand does, so why don't you enlighten the rest of us with your better/correct knowledge at your own site? Or has that been done already?Just saying...
jordanclock - Saturday, September 19, 2009 - link
I'm currently in the process of putting together a new system and the choice between the i5 750 and the i7 860 is very hard. The 920 isn't even an option for me; The 860 outperforms the 920 in most scenarios, and when the 920 comes ahead, it's less than the margin of error.Are you looking at the same graphs I am? The ones that show the 860 performing better, or at worst identically, to the 920 over and over? For the same CPU price and lower motherboard price? This isn't a Celeron. This isn't something you pair up with an IGP. This is the current generations upper-end bang-for-the-buck champion.
Add in the 750, and I see no reason to get a 920. Two-thirds the price, with most of the benchmarks showing performance parity, sometimes a little less. Again, with a lower motherboard cost as well.
If anything, the 920 is the solution searching for a problem. The 860 just took over the job of the 920, except for a few cases. The 750 offers almost the same performance, but at an even lower cost.
These chips aren't brain-damaged; They just took out the cancerous tumors. Lower cost, lower power, and equal performance. The 860 stole the 920's thunder, and the 750 gives us a very complete mid-range.
the zorro - Saturday, September 19, 2009 - link
if you go to newegg you can see that lynnfield is not selling, because is crippled, expensive and phenom 2 wipes and mops the floor with core i5 750.KoolAidMan1 - Saturday, September 19, 2009 - link
You are either deluded or trolling. The i5 720 both costs less and outperforms the Phenom II X4 965 BE in pretty much every chart.