Intel's Core i7 870 & i5 750, Lynnfield: Harder, Better, Faster Strongerby Anand Lal Shimpi on September 8, 2009 12:00 AM EST
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Intel is on the verge of transitioning to 32nm. We'll see the first parts this year. What do you do with your 45nm fabs when you start moving volume away from them? Make really cheap quad-core Nehalems of course:
I'm talking $196. I'm talking faster than AMD's entire lineup. I'm talking about arguably the best processor of 2009. I'm talking about Lynnfield, and here's its backside:
I spent much of the past year harping on AMD selling Nehalem-sized Phenom IIs for less than Intel sold Nehalems. With Lynnfield, Intel actually made Nehalem even bigger all while driving prices down. Like I said, what do you do when you're still making boatloads of money in a recession and are about to start emptying your 45nm fabs?
I should clear things up before we progress much further. Lynnfield is the codename for mainstream 45nm quad-core Nehalem, while Bloomfield refers to the first Nehalem launched at the end of 2008:
|Processor||Manufacturing Process||Die Size||Transistor Count||Socket|
Despite being cheaper, Lynnfield is larger than Bloomfield. The larger die is due to one major addition: an on-die PCIe controller.
Bloomfield, The First Nehalem, circa 2008
Lynnfield, Nehalem for All, circa 2009
The pink block to the right of the die is the PCIe controller, that's 16 PCIe 2.0 lanes coming right off the chip. Say hello to ultra low latency GPU communication. You'd think that Intel was about to enter the graphics market or something with a design like this.
Sacrifices were made to reduce CPU, socket and board complexity. Gone are the two QPI links that each provided 25.6GB/s of bandwidth to other CPUs or chips on the motherboard. We also lose one of the three 64-bit DDR3 memory channels, Lynnfield only has two like a normal processor (silly overachieving Bloomfield).
Intel's Bloomfield Platform (X58 + LGA-1366)
The sum is that Lynnfield is exclusively single-socket; there will be no LGA-1156 Skulltrail. While the dual-channel memory controller isn't really a limitation for quad-core parts, six and eight core designs may be better suited for LGA-1366.
Intel's Lynnfield Platform (P55 + LGA-1156)
The loss of QPI means that Lynnfield doesn't have a super fast connection to the rest of the system, but with an on-die PCIe controller it doesn't matter: the GPU is fed right off the CPU.
We get three Lynnfield CPUs today: the Core i7 870, Core i7 860 and the Core i5 750. Intel's branding folks told us that the naming would make sense one we saw the rest of the "Core" parts introduced; yeah that was pretty much a lie. At least there aren't any overlapping part numbers (e.g. Core i5 860 and Core i7 860).
The i7 in this case denotes four cores + Hyper Threading, the i5 means four cores but no Hyper Threading. The rules get more complicated as you bring notebooks into the fray but let's momentarily bask in marginal simplicity.
|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|
Keeping Hyper Threading off of the Core i5 is purely done to limit performance. There aren't any yield reasons why HT couldn't be enabled.
Intel was very careful with both pricing and performance of its Lynnfield processors. I'm going to go ahead and say it right now, there's no need for any LGA-1366 processors slower than a Core i7 965:
This is only one benchmark, but it's representative of what you're about to see. The Core i7 870 (LGA-1156) is as fast, if not faster, than every single LGA-1366 processor except for the ones that cost $999. Its pricing is competitive as well:
For $196 you're getting a processor that's faster than the Core i7 920. I'm not taking into account motherboard prices either, which are anywhere from $50 - $100 cheaper for LGA-1156 boards. I don't believe LGA-1366 is dead, but there's absolutely no reason to buy anything slower than a 965 if you're going that route.
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lordmetroid - Tuesday, September 8, 2009 - linkI am using Linux!
andrenb91 - Wednesday, September 9, 2009 - linkc'mon probably u still running windows for somethings...wine doesn't work owith every thin...i run liux on dual boot for years and still trying to make wine run fligh simulator x..which is the only game I play...remember, these benchmarkes are only for win bases pcs, in linux the history is diferent, see it at phoronix.com...
james jwb - Tuesday, September 8, 2009 - linkis turbo boost on for the benchmarks?
snakeoil - Tuesday, September 8, 2009 - linkyes they benchmarked with turbo boost, that is cheating because thats overclocking the processor at least 600 mhz and presenting the results as it were at stock speeds.
that's abusing the reader's trust.
maxxcool - Tuesday, September 8, 2009 - linkHahaha, you are just as much of a idiot here as on techreport snake! ... did you come here and claim to have proof that i5 will not run xp-mode to?
hahahaha, your just sad that Amd did not come up with this feature 1st.
Jarp Habib - Tuesday, September 8, 2009 - link"yes they benchmarked with turbo boost, that is cheating because thats overclocking the processor at least 600 mhz and presenting the results as it were at stock speeds.
that's abusing the reader's trust. "
This statement is a load of bullcrap. Anand's intent is to present the benchmarks in a way reflective of the chip's standard performance in normal use- hence not manually overclocking for maximized performance. The processor's very design revolves on itself automatically shutting down inactive cores and boosting the speed of active cores, *regardless* of what the end user does to the chip in BIOS or what apps he's running. Since all you need to do to use Turbo Boost is just *install the CPU in your system* then benchmarks should be run with it enabled.
If you want to COMPLETELY level the playing field, then TurboBoost should be shut down, for both Bloomfield i7 chips and Lynnfield i5 AND Lynnfield i7, as well as future i3 and i9. Also, HyperThreading must be disabled from all chips, 3DNow!, SpeedStep, Cool N' Quiet, MMX and the entire SSE instruction sets. After all, each different type of CPU executes those standard instruction sets differently. And since the SpeedStep and Cool N Quiet instructions force the chip to underclock and shut off cores while at idle, they must be eliminated from testing as well, or they'll throw off your idle power consumption benchmarks.
Since you will be normalizing the clock frequencies as well, you can save time by only needing to test just one chip from each product line. I'm not sure just how you will normalize the clock frequencies of your test units *without overclocking or underclocking* some of them though. Perhaps you'll let me know?
Meanwhile, back in the real world...
Voo - Tuesday, September 8, 2009 - linkThe difference is, that turbo mode impairs the possible benefit of overclocking the chip, while most things you enumerated do not.
If you want to get the maximum out of the 860 you've got to disable turbo mode as we see in the review, so for everyone who'd want to overclock their CPU the most interesting test would be a comparison between the two chips both at their maximum stable performance. Which at the moment means disabling turbo mode as we can see.
erple2 - Tuesday, September 8, 2009 - linkA-HA! So really, you're just interested in the benchmark "What does the maximum overclock do", not "How does the CPU perform at normal operations". BTW, does disabling HT does improve overclocking a little bit, so should that also be disabled? Cool-n-Quiet plus SpeedStep may also affect overclocking capabilities. Should those be disabled? I fail to see the difference between what the GP said and your justifications.
MadMan007 - Tuesday, September 8, 2009 - linkI'm not bothered by enabled Turboboost in a 'stock speed' review either but I would really like to see more sites run their benchmark suite with 3.6-4.0GHz (or higher) C2D, C2Q and Phenom II versus overclocked but non-Turboboost i5/i7. The reason is that this type of comparison would be most directly useful for the site's enthusiast readerships to know what the actual difference between *their rig* and an i5/i7 would be.
Kaleid - Thursday, September 10, 2009 - linkSeconded.