Nehalem will support 2-way SMT (two threads per core), much like the Pentium 4 did before it. With a shorter pipeline than NetBurst and a greater ability to get data to the cores, there's more opportunity for increased parallelism (and thus performance) thanks to SMT on Nehalem than on Pentium 4.

The cache subsystem of Nehalem is almost entirely changed from Penryn. While Nehalem has the same 32KB L1 instruction and data caches of Penryn, the L2 and L3 caches are brand new. Each core in a quad-core Nehalem now has a smaller 256KB L2 cache, which Intel is calling "low latency" (potentially lower latency than Penryn thanks to a smaller cache size). While ditching the shared L2, Intel equipped Nehalem with a large 8MB fully-shared L3 cache that can be used by all cores.

This setup seems very similar to AMD's Phenom architecture, obviously built on Intel's Core 2 base however - the major difference here is that the cache hierarchy is inclusive and not exclusive like AMD's. The inclusive architecture means that each level of cache has a copy of data from the lower cache levels.

Nehalem effectively includes the only remaining advantages AMD held over Intel with respect to memory performance and interconnect speed - you can expect a tremendous performance increase going from Penryn to Nehalem because of this. Intel is expecting memory accesses to be around twice the speed in Nehalem as they are in Penryn, which thanks to its aggressive prefetchers are already incredibly fast. If you think Intel's performance advantage is significant today, Nehalem should completely redefine your perspective - AMD needs its Bobcat and Bulldozer cores if it is going to want to compete.

Intel has also added a new 2nd level TLB in Nehalem, similar in approach to its new 2nd level branch predictor. The first level TLB does a good job of keeping the cores fed quickly, but if there isn't a physical/virtual address mapping found in the first level TLB Nehalem can now look in the second level TLB instead of looking in the cache to keep performance high and latency low.

The TLB enhancements in particular look to be particularly great at server workloads, we suspect that Intel may be looking to really take on Opteron with Nehalem.

Above you see examples of the first Nehalem platforms - they should look very familiar to block diagrams of AMD K8 platforms we've seen for years now. The first high end desktop Nehalem parts will have an integrated 3-channel DDR3 memory controller supporting DDR3-800, 1066 and 1333.

On the server side you'll see registered memory support from Nehalem's IMC.

Nehalem Architecture: Improvements Detailed Intel 32nm Update
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  • dreddly - Wednesday, March 19, 2008 - link

    Your stubborn refusal to acknowledge the repeated objections to the insertion of a sexually inappropriate innuendo into the headline does not constitute 'vague mutterings'.

    If this site persistently juxtaposed sexually charged images of women with their headlines (akin to maxim) to make a literary statements or metaphors, then it would not be an issue. The objection is to complete irrelevance and seeming ignorant refusal to justify why the image of a Japanese women was chosen and why a traditionally conservative and respectful piece of clothing -the kimono- became the focal point for 'exposure'.

    The point you have consistently ignored is that if we replace the image of the Japanese women with a man or a image of a woman on the beach, the non-nonsensical nature of the headline is overly and absurdly apparent.

    Your persistent attempts to imply that this argument is anti-sex is as laughable as your understanding of contemporary feminism. If anandtech has decided to go the maxim route, fine, there is an range of arguments and a justifiable reasons to counterpose technology and sex. The problem is that there is no justification or purpose for the headline - it isn't very literary and doesn't relate to the overall purpose of the site. As such, it is a superficial and unnecessary trope, the use of which DOES replicate and connotate a persistent stereotype of sexualized asian women. The use of the stereotype out of ironic or literary context appears to be DESIGNED to offend women and asians who object to those oversimplications that have often used to discriminate and marginalize in the past.
  • Screammit - Sunday, March 23, 2008 - link

    "The use of the stereotype out of ironic or literary context appears to be DESIGNED to offend women and asians..."

    I'm totally with you on this Anandtech marginalization conspiracy theory, but i'm pretty sure the girl in the picture did something to deserve it. I was kinda hoping for the new Nehalem chips to be used as pasties, but hey, there's always the next article, right?
  • hobel - Tuesday, March 18, 2008 - link

    You are the only who thinks that a kimono is womans clothing only.
    In the context with the image, ok... but the headline only is gender neutral. Or never seen a sumo ringer in kimono?
  • jasongg06 - Tuesday, March 18, 2008 - link

    Well put. This title is inappropriate. Not only is it offensive to women, it is also offensive to Asians in general. You'd think in 2008 people would have better taste and judgment.
  • masher2 - Tuesday, March 18, 2008 - link

    > "it is also offensive to Asians in general..."

    The headline implies:

    a) That somewhere in the world, some women still wear kimonos, at least under some circumstances.
    b) That at least some men still remain sexually attracted to women.

    Which of these suggestions is "offensive to Asians in general"?
  • ocyl - Tuesday, March 18, 2008 - link

    Agreed. I don't think that the article title and the front-page image are appropriate, either, considering that there is no need to sensitize / emotionalize the subject matter.
  • madoka - Tuesday, March 18, 2008 - link

    Yes, the title and imagery is pretty crass and tasteless.
  • masher2 - Monday, March 17, 2008 - link

    I commend you on your ability to be offended by pointless trivia.
  • Griswold - Tuesday, March 18, 2008 - link

    Good thing you're not the authority on what is "pointless trivia" and what is not.
  • Tilmitt - Monday, March 17, 2008 - link

    As someone with a Japanese girlfriend...I loved the title!

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