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
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:
Mmm
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 |
Bloomfield | 45nm | 263 mm2 | 731M | LGA-1366 |
Lynnfield | 45nm | 296 mm2 | 774M | LGA-1156 |
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.
The Lineup
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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HexiumVII - Tuesday, September 8, 2009 - link
I must say that Lynnfield is the best stock processor ever. It will o/c itself without you having to touch it at all. Nearly perfect for the masses. I absolutely can't wait for the notebook incarnation.ClagMaster - Tuesday, September 8, 2009 - link
The performance of these processors is what I thought they would be based on your May Preview Article. Its great the NDA is lifted and we can now see what this processor can really do.This is hardly a Celeron. I know a troll in earlier Lynnfield/P55 that should be eating crow.
Apahutec - Tuesday, September 8, 2009 - link
Not sure what "core parking" priorities are (reduce power consumption by grouping tasks on active CPUs, or tune performance by taking into account cache trashing in scheduler decisions), but it sounds like it could even be beneficial on my Core 2 Quad: single socket, no HT, but two Core2 Duo (each with its own L2 cache) glued together.erple2 - Tuesday, September 8, 2009 - link
Sounds like it, but the logic that controls that on the CPU is on the CPU, and uses up a couple million transistors. That would require a re-spin of the Core 2 parts (which, given the P55 platform release, I think is a safe bet won't happen), however.Obsy - Tuesday, September 8, 2009 - link
I don't get how Turbo Boost ends "dual-core or quad-core?" I know that an on-die IGP is a selling point for the upcoming 32nm dual cores, but wouldn't they be clocked higher than these quads and have Turbo Boost too? There will be dual cores clocked higher than quads again. Or is Intel not clocking their dual cores past the speeds of quads?macs - Tuesday, September 8, 2009 - link
Would be interesting an article about P55 mobo with nf200 chip and 2 gpu...Ryan Smith - Tuesday, September 8, 2009 - link
We talked to NVIDIA about that scenario a couple of weeks ago. A NF200 chip would not make a significant difference in performance, which is why they're letting manufacturers go ahead and just split lanes with a straight-up bridge chip.Darkanyons - Tuesday, September 8, 2009 - link
Thanks for this great article!!Tomzi - Tuesday, September 8, 2009 - link
Do the PCIe controller's voltage demands impose stricter limits on undervolting in the case of Lynnfield processors compared to Bloomfield? I can run my i7 920 at stock frequncies undervolted to 0.9xx V VCore. How much voltage (power consumption) reduction can we expect from the an i5 750?This might not be a hot topic so close to the release of the new chips when everyone is focused on top performance comparisons but I've always been interested in undervolting/clocking and would like to see a more complete picture.
Tomzi - Tuesday, September 8, 2009 - link
750 and 870 undervolted by ~0.1V reported on silentpcreview.