Intel Core i5 And Core i7: Intel’s Mainstream Magnum Opus

What’s In A Name?

With Core 2 Quad and Core 2 Duo, you had a general idea of what you were dealing with upfront. Adding a Q8000- or E7000-series designator wasn’t particularly descriptive, but at least there was one tangible identifier in there for the layman to digest.

When Intel introduced Core i7 last year, the fact that there was only one Nehalem-based desktop family made it easy to say “Core i7—yeah, high-end stuff,” regardless of whether you were actually talking about the $300 i7-920 or the $1,000 i7-965.

Core i7, Core i5, and Core 2 QuadCore i7, Core i5, and Core 2 Quad

Now you have Core i5 and another strain of Core i7; at this point the nomenclature is just jargon for everyone except for the power users who live and breathe this stuff. Let’s break it down in a neat little table, though.


Core i7 (LGA 1366)
Core i7 (LGA 1156)
Core i5
Core 2 Quad
Processor Interface
LGA 1366
LGA 1156
LGA 1156
LGA 775
Number of Cores
4
4
4
4
Turbo Boost
Yes
Yes
Yes
No
Hyper-Threading
Yes
Yes
No
No
L1 Cache
32KB/32KB per core
32KB/32KB per core
32KB/32KB per core
32KB/32KB per core
L2 Cache
256KB per core
256KB per core
256KB per core
Up to 12MB shared
L3 Cache
8MB shared
8MB shared
8MB shared
No
Memory Channels
3
2
2
2
Max. Memory Rate
DDR3-1066
DDR3-1333
DDR3-1333
DDR3-1600
Chipset
X58
P55
P55
X48
Price
$284-$999
$285-$555
$199
$163-$316


As you can see, Core i7 for LGA 1366 remains the enthusiast-class offering, sporting the most PCI Express 2.0 connectivity via Intel’s X58 Express chipset, up to three available channels of DDR3 memory support, Intel’s first generation of Turbo Boost, and Hyper-Threading.

Core i7-870Core i7-870Core i5-750Core i5-750

Core i7 for LGA 1156 integrates the PCI Express connectivity (albeit 16 lanes instead of 36), sheds one memory channel, incorporates an updated implementation of Turbo Boost, and maintains Hyper-Threading support.

Core i5 includes the same on-board PCI Express subsystem and dual-channel integrated memory controller. It employs Intel’s improved Turbo Boost (though it’s slightly less aggressive than i7’s). What it lacks, however, is Hyper-Threading—apparently a noteworthy-enough capability to turn an i7 into an i5. Of course, descending the stack also results in lower base clock rates.

The Making Of A Core i5/i7

Architecturally, most of what you get in a Core i5 or Core i7 processor is borrowed from technology already found in Intel’s LGA 1366-based Core i7 and Xeon 3500-series processors. The Lynnfield die is different from Bloomfield though, estimated at 774 million transistors packed into 296 square millimeters (versus 731 million in 263 millimeters for the first Core i7s). More than 400 million of those transistors make up the CPU's cache.

As with Bloomfield, Lynnfield is a monolithic design divided into four cores (execution pipelines, L1 data/instruction cache, TLBs) and the uncore (L3 cache, integrated PCI Express, the memory controller, QPI, and the PLLs). The power for these two “halves” remains separate, independently adjustable in your motherboard's BIOS.

Bloomfield: core vs. uncoreBloomfield: core vs. uncore

Each of the four cores retains its 32KB L1 data cache (still 8-way set-associative), 32KB L1 instruction cache (still 4-way set-associative), and 256KB L2 cache (you guessed it—still 8-way set associative). An inclusive 8MB L3 cache 16-way set-associative) should look familiar as well. 

With nothing really new to report in the cores themselves, we move to the uncore, where Intel has added PCI Express 2.0 connectivity, axed a single memory channel, dropping the total to two, and altered QPI.

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    Top Comments
  • cabose369
    Intel needs to come up with a simplified naming system for their products. They are as bad as NVIDIA is right now in terms of naming their products.

    There is sooo much to learn and there is so much information here.... I feel confused!!
    15
  • JeanLuc
    The AMD Phenom II X4 965 BE is running at 3.4Ghz.............I can remember only a few years ago AMD bragged about getting 'more work done per cycle' where as Intel responded by increasing the clockrate. It now looks like the tables have completely turned and it's AMD that has to keep increasing the CPU frequency to stay competitive.
    11
  • evolve60
    "Intel Core i7-920 Extreme (Bloomfield) 2.66 GHz, LGA 1366, 4.8 GT/s QPI, 8 MB L3, Power-savings enabled"

    Since when has the I7-920 become an extreme?
    11
  • Other Comments
  • caamsa
    Dang! AMD better get their $4iT together. Now I need to decided between i7, i5 or phenom II when I do my next upgrade........technology happens too fast. Looking forward to more reviews on the i5 and mb prices.
    3
  • Anonymous
    People need to be careful when comparing the i7-870 to a i7-920, alot of people pre-release were worried that the 1156 platform was going to dominate the 1366. However when you see the 870 out perform the 920 people need to remember that a 870 is double the price of a 920, and even when you factor in a motherboard a 920 setup comes out cheaper than a 870.

    Now the i5 750 on the other hand is great performance at a great price, and would certainly be the budget gamers new weapon of choice.

    I currently have an i7-920 setup which is my main rig and am very happy with it and not at all upset to the see the 870 outperform it (since the 870 would cost me twice as much). I also have had an i5 750 setup now for over a week (the 1156 processors and motherboards have been available here in Australia for nearly 2 weeks now) and it is an amazing processor for the price of it.

    So what am I trying to say? 1366 is still a good platform for the top end of the market. The i5 are fantastic new processors for their price, and the 1156 i7's are just confusing and I'm not really sure who they are going to appeal to? I could understand it if Intel launched the 1156 i7's in 6months time when alot of users are already using the 1156 platform and are looking to upgrade their CPU without a new mobo. But to anyone looking at getting a 870, just get an 920 and use the extra cash on the mobo and ram to go with it.
    3
  • Nintendork
    A little confusing the charts.

    I would prefer a bench with HD4890. They scale better in CF.
    8
  • aspireonelover
    I can tell, I'm gonna fall in love with the i5 processor
    0
  • cabose369
    Intel needs to come up with a simplified naming system for their products. They are as bad as NVIDIA is right now in terms of naming their products.

    There is sooo much to learn and there is so much information here.... I feel confused!!
    15
  • alikum
    Well, I just hope that the Core 2 Quads will drop in prices significantly so that I could grab the high-end one for my final LGA775 upgrade!
    1
  • buzznut
    Well this is good news for consumers. I'm not certain why it took so long for Intel to make some mainstream proc like i5, but for intel fans it seems worth the wait.
    This will also compel AMD to bring some more value to the market. Nice article.
    3
  • jawshoeaw
    damn, 150 watts at idle?? Is that just the cpu? I hope the gaming rigs built on these processors are not left on 24/7. My old AMD X2 3800 system including the monitor uses less than 150 watts at idle (50 of which is the 22" LCD).
    -4
  • unclewebb
    i7 Turbo is a good tool to monitor the multiplier of Core i5/i7 CPUs.

    http://www.fileden.com/files/2008/3/3/1794507/Turbo.zip

    It uses the method that Intel recommends in their November 2008 Turbo White Paper.
    1
  • evolve60
    "Intel Core i7-920 Extreme (Bloomfield) 2.66 GHz, LGA 1366, 4.8 GT/s QPI, 8 MB L3, Power-savings enabled"

    Since when has the I7-920 become an extreme?
    11
  • Dekasav
    jawshoeawdamn, 150 watts at idle?? Is that just the cpu? I hope the gaming rigs built on these processors are not left on 24/7. My old AMD X2 3800 system including the monitor uses less than 150 watts at idle (50 of which is the 22" LCD).


    The power readings are for the whole system, not just the CPU. And their readings are a bit higher than yours because their video cards are almost certainly more power-hungry than yours, and they have a quad-core cpu, running significantly faster than your dual-core (4 cores at ~3Ghz vs. 2 at ~2Ghz, which SHOULD use more power?)
    3
  • dragonsprayer
    Nice article as always THG rules! Ouch amd!

    hey guys some tests done at the same cpu speed would be helpfull! thx!
    1
  • cangelini
    Thanks Dragon--check out the In Theory piece that also went up today. It has i5, i7, i7 LGA1366, Core 2, and Phenom II at 2.8 GHz in a bunch of games!
    0
  • th_at
    Deekay_alot of people pre-release were worried that the 1156 platform was going to dominate the 1366.


    Who was "worried"? It would've been AWESOME (although not to expect of Intel) if the lower-price platform would've outperformed the high-end item.
    2
  • cangelini
    evolve60"Intel Core i7-920 Extreme (Bloomfield) 2.66 GHz, LGA 1366, 4.8 GT/s QPI, 8 MB L3, Power-savings enabled"Since when has the I7-920 become an extreme?


    Typo--thanks for the catch evolve. Pulled that table from a previous review and missed the Extreme!
    0
  • dragonsprayer
    Also - this address people above too and the article.
    When you set up an i7 system you turn off the HT and turn up the speed! Turning off a core might even be an upgrade for some. But i agree, the i5 is really a good plateform the mid-mid high level people and at a lower price.

    above - too long for intel? for main stream? you could buy a 8400 and run it 3.8 in any system and it rocks.

    people have to learn that overclocking is not what it once was, intel does not build all that into the procesor and chipset for nothing so use it! core 2 is still a good main steam system, abit, no upgrading
    -1
  • Korok
    Where is the i7 860?

    Great read, by the way
    All the mixed rumors were really misleading
    1
  • Intel_ARK_Dude
    FYI: All of the Lynnfield-based parts are here:
    http://bit.ly/Lynnfield

    And a side-by-side comparison with all the key stats are here:
    http://bit.ly/LFDcomparison
    3
  • bigdaddycool
    The problem with Intel no matter how special they make they CPU's is they have absolute crap when it comes to motherboards.

    AMD is feature packed, Intel is feature lacked.

    Intel make good chipsets yes, Intel make good reliable boards (proper intel boards) yes, intel make good CPU's yes.

    But Intel have worthless motherboard line ups.... I am happily an AMD fan, I will take my Phenom II with the slower speed for the quality of board I can buy to run it.

    Intel & Motherboards = Fail.

    Until they improve there, numbers mean zero to me. Why pay more when you get less?

    PS. We used to sell all Intel at my work, we now sell 99% AMD. Price, value as a packaged. If Intel had better feature motherboards things might change until then. AMD builds a platform not just a CPU.
    -9
  • JeanLuc
    The AMD Phenom II X4 965 BE is running at 3.4Ghz.............I can remember only a few years ago AMD bragged about getting 'more work done per cycle' where as Intel responded by increasing the clockrate. It now looks like the tables have completely turned and it's AMD that has to keep increasing the CPU frequency to stay competitive.
    11