Intel Core i7 (Nehalem): Architecture By AMD?

Two years ago, Intel pulled off a coup with the introduction of its Conroe architecture, which surfaced as the Core 2 Duo and Core 2 Quad. With this move, the company won back the performance crown after losing a bit of favor in the debacle that was its Pentium 4 "Prescott" design. At that time, Intel announced an ambitious plan to return to evolving their processor architectures at a rapid pace, as they had done in the mid-1990s. The first phase of the plan was the release of a “refresh” of the architecture 12 months after its introduction, to take advantage of progress in fabrication processes. That was done with Penryn. Then a whole new architecture was set to arrive 24 months later, with the code name Nehalem. That new architecture is the subject of this article.

The Conroe architecture offered first-rate performance and very reasonable power consumption, but it was far from perfect. Admittedly, the conditions under which it was developed weren’t ideal. When Intel realized its Pentium 4 was a dead-end, it had to reinvent an architecture in a hurry—something that’s far from easy for a company the size of Intel. The team of engineers in Haifa, Israel that, up until then had had responsibility for mobile architectures, was suddenly responsible for providing a design that’d power the entire new line of Intel processors. It was a challenging task for the team, which now bore Intel’s future on its shoulders. Given those conditions—with the tight schedule they had to stick to and the pressure they were under—the results that the Intel engineers achieved are remarkable. The situation also explains why the team had to make some compromises.

Although it was a serious reworking of the Pentium M, the Conroe architecture still sometimes betrayed its mobile roots. For one thing, the architecture wasn’t really modular. It had to cover the entire Intel range, from notebooks to servers. But in practice, it was practically the same chip in each case; the only place for variation was in the L2 cache memory. The architecture was also clearly designed to be dual-core, and moving to a quad-core version required the same kind of trick that Intel had resorted to for its first dual-core processors—two dies in a single package. The presence of the FSB also hampered the development of configurations using several processors, since it was a bottleneck in terms of memory access. And a final little giveaway: one of the new features introduced with the Conroe architecture—macro-ops fusion—which combines two x86 instructions into a single one, didn’t work in 64-bit mode, the standard operating mode for servers.

These compromises were understandable two years ago, but today Intel can no longer justify them—especially when faced with its rival AMD and the Opteron processor still a compelling play for enterprise environments. With Nehalem, Intel needed to remedy its last weaknesses by designing a modular architecture that could adapt to the differing needs of the all three major markets: mobile, desktop and server.

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  • americanbrian
    While undoubtedly this will create a whole new level of performance. I imagine it will be prohibitively expensive. Coming in just as the global economy hits a trough.

    For this reason I think AMD has a brighter future when it releases it's new 45nm cores. They will provide a good performance increase and I am willing to bet will still trump intel on the price/performace scale.
  • mi1ez
    Fantastic article, very insightful.
  • M_Taylor40
    First off, I have not read the entire article but I just want to comment on the name.
    I've been saying this since they announced the design of Nehalem, its Intels take on AMD design, which means your getting the best of both companies as AMD designs have been so much better than Intel but AMD could not challenge what Intel already had.
    It's been a long time coming for Intel to adopt AMD's designs but I really do look forward to the release (Well 6 months after when I might be able to afford a Core i7 system!), but feel AMD really needs to pull something out the hat to compete.
    Anyways, from what I have read, its a good article lol.
  • goozaymunanos

    btw, where's the 8-core systems we were promised for 2008?

    ..and where's all the re complied apps to take advantage of all this processing parallelism?!

    p.s. stuff and nonsense:
  • eriko
    My credit card is restless...
  • Anonymous
    just hope the bank is still around to honour your credit card... :D
  • bobwya
    Now that's more like it!! A well informed article, that is well written and imparts some useful information... More of the same please THG!!

    I'm just off to sell those AMD shares...

  • jammydodger
    While the article is sound, it did upset me the at the first two pages talk about the 'Conroe' architecture. 'Core 2' is the name of the architecture used in the Conroe line of processors. 'Conroe' is the name given to the first desktop iteration of the core2 architecture, just as Allendale is the value version and Kentsfield the quad core version (along with all the new iterations that utilize different cache sizes or manufacturing process).

    It is difficult to inspire confidence in your readers when such obvious mistakes are apparent.
  • KingGreatYat
    Jammydodger : I think the usage may be a little off, but to say the conroe architecture, just means the uarch used by the conroe chips - which is in common with all chips of the generation. Also, the architecture was refered to by the code name Merom . Core 2 is a retail brand name. Either way, this is a minor mistake and not something that would make me doubt the validity of the article.
  • szilu2002
    at last a quality oriented article!!!
    Complete and detailed i want to see more in the future!
  • jammydodger
    KingGreatYat: I do realise that I could be seen to be splitting hairs, but when an article goes in to such detail about an upcoming processor architecture but begins the article by failing to recognise the distinction between an architecture and a core then it does raise the question of whether the writer has fully understood what it is that he is trying to impart upon us. If I were to begin an article by talking about intel's 'Northwood' architecture then I would be talking non-sense, Northwood was a chip based around Intel's 'Netburst' architecture. The Merom is, as far as I am aware, the first mobile variant of the Core2 architecture, it was proceeded by the Yonah based on Intel's 'Core' architecture, which was itself based on the 'P6' architecture.
  • krisna159
    competition is good for the market,end user like us have many choises to pick,AMD or intel.i agreed with americanbrian.lets wait the counter attack from AMD with the lates technologies n off course with lowest price.
  • geoffy
    Intel says the problem is solved now, but provides no details on the operation of the new prefetch algorithms

    Something tells me this is going to be pivotal if Deneb proves to be any good...

    Great article, by the way, minor niggles aside!