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Intel Hardware Technology

Inside Intel's Core i7 Processor, Nehalem 146

Posted by Soulskill
from the upgrades dept.
MojoKid writes "Intel's next-generation CPU microarchitecture, which was recently given the official processor family name of 'Core i7,' was one of the big topics of discussion at IDF. Intel claims that Nehalem represents its biggest platform architecture change to date. This might be true, but it is not a from-the-ground-up, completely new architecture either. Intel representatives disclosed that Nehalem 'shares a significant portion of the P6 gene pool,' does not include many new instructions, and has approximately the same length pipeline as Penryn. Nehalem is built upon Penryn, but with significant architectural changes (full webcast) to improve performance and power efficiency. Nehalem also brings Hyper-Threading back to Intel processors, and while Hyper-Threading has been criticized in the past as being energy inefficient, Intel claims their current iteration of Hyper-Threading on Nehalem is much better in that regard." Update: 8/23 00:35 by SS: Reader Spatial points out Anandtech's analysis of Nehalem.
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Inside Intel's Core i7 Processor, Nehalem

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  • by Anonymous Coward on Friday August 22, 2008 @08:06PM (#24713979)

    The problem with hyperthreading is that it fails to deal with the fundamental problem of memory bandwidth and latency in the x86 architecture. It's true, some apps will see a 20% or better improvement in performance, but most won't see anything more than a marginal increase.

    Still, if one can safely enable hyperthreading without slowing down your system, unlike the last time we went through this, we should consider it a success. Hopefully, Quickpath will provide the needed memory improvements.

    • I for one... (Score:1, Insightful)

      by Anonymous Coward

      I for one welcome the death of FSB and all that, but yet again it means a new motherboard, a new CPU socket and all that (DDR3 too). Better save up!

      • by turgid (580780)

        I for one welcome the death of FSB and all that, but yet again it means a new motherboard, a new CPU socket and all that

        I did that a couple of years back. I've gone from a single core Athlon 64 at 2.0GHz to a dual core at 2.6GHz and I'll be going quad core in a month or two, all with the same motherboard and RAM (and everything else). OK I might buy some faster RAM, but in theory I could still use the old stuff.

        Hypertransport came out in 2003. It's 2008 and intel has only just got its competitor out.

        If

    • by thecheatah (977630) on Saturday August 23, 2008 @02:51AM (#24716401)
      The problem that you describe can also be applied to having multiple cores. If you read the article you will realize that they have taken MANY steps to prevent this.
      For one they use ddr3 memory. Another thing is that they have much more intelligent pre-fetching mixed with the loop detection thingy. The cache size/design itself allows for many applications to run.
      The problem that you describe is a problem with the OS's scheduler. It should understand the architecture that it is running on. It should know about the types of caches the way each processor shares them. etc. Thus, it only makes sense to use hyper-threading if 1. you are simply out of cores (the choice of using ht cores is iffy) 2. a single application has spawned multiple threads. Even then you have to take into account the availability of other cores that share the l2 or l3 cache.
      I personally think that intelligent pre-fetching and loop detection thingy is something that needs more tests/statistics thrown at.
      Like you say, there are some applications that take advantage of HT let them take advantage of it while writing smarter OSs that understand the problems with doing so.
      Maybe they need a feed back mechanism from the processor for the OS to understand what is the best way to schedule tasks.

      I dont know much about CPUS :-p, just from what I read and learned in school.
    • erm, loop stream detection?

      maybe this iteration iNTEL will burn for their sins.

    • by TheRaven64 (641858) on Saturday August 23, 2008 @07:23AM (#24717407) Journal

      The problem with hyperthreading is that it fails to deal with the fundamental problem of memory bandwidth and latency

      The entire point of SMT (of which HT is am implementation) is that it helps hide memory latency. If one thread stalls waiting for memory then the other gets to use the CPU. Without SMT, then a cache miss stalls the entire core. With SMT, it stalls one context but the other can keep executing until it gets a cache miss, which hopefully doesn't happen until the other one has resumed.

  • DNF (Score:2, Funny)

    Meh. I'm still waiting for multicore quantum computing. Or at least something that can execute code that doesn't exist yet, so i can play Duke Nukem Forever. Actually, what I really want is a processor that can execute code by its spirit, rather than its letter, so buggy code will work correctly anyway. :-)
  • by Anonymous Coward
    'nuff said?
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      As a matter of fact, the technology was called Simultaneous Multithreading (SMT) when it was developed by Digital Equipment and the University of Washington, long before Intel marketeers got their hands on it.

  • Is it 3.999999999 more accurate?
  • by Joe The Dragon (967727) on Friday August 22, 2008 @08:17PM (#24714077)

    only the super high desk tops have Quick Path and Triple channel DDR3 and the bigger joke is the that there will be 2 differnt 1 cpu desktop Socket.

    also the mobile will not have Quick Path.

    all AMD cpus use hyper transport and all desktops will use the same socket and the upcoming AM3 cpus will work in the older am2+ boards. Also on amd you can use more then 1 chipset will intel it looks like you will be locked in to a intel chipset.

    • by doyoulikeworms (1094003) on Friday August 22, 2008 @08:45PM (#24714249)
      I'm pretty sure the parent post was written by a machine. Turing test: failed.
    • by beakerMeep (716990) on Friday August 22, 2008 @09:19PM (#24714475)
      Take a deep breath. It's OK if AMD and intel both have good chips. The question really comes down to the brand of salsa anyways.
    • Re: (Score:1, Funny)

      by Anonymous Coward

      >only the super high desk tops have Quick Path and Triple channel DDR3

      So, you're saying that Intel is also supplying marijuana with these systems?

      Sold!

    • Re: (Score:3, Insightful)

      by moozh84 (919301)
      You won't be locked into an Intel chipset. Obviously NVIDIA will be making chipsets for Nehalem processors. So with Intel processors you will have Intel and NVIDIA chipsets. With AMD processors you will have AMD and NVIDIA chipsets. It won't be much different than it currently is, except most likely VIA will completely drop out of the market in favor of other ventures.
      • Obviously? I really doubt nVidia will be able to make chipsets for Intel. And if they can it'll be crap ones, and even worse than typical nForces because they won't have QuickPath.

        • by darien (180561)

          Nvidia won't be competing with the initial X58 chipset, but they do plan to start supporting Nehalem at some point after launch.

      • by drinkypoo (153816)

        You won't be locked into an Intel chipset.

        You already are locked into an intel chipset; if you want reliability with an intel CPU, you need an intel chipset. I have always been sadly disappointed with any non-intel chipset. Things vary in AMD-land, but they're not all that much different there; I always shop for a board with an AMD chipset. It will probably not be the fastest, but it will probably work.

    • Actually I don't know if they are cutting their own throat or not,but I have noticed I'm building a lot more AMD machines lately. And for the first time since the old K2(IIRC,they were the 400MHz ones) I am actually looking at building an AMD board for myself. The price on AMD dual cores has just gotten so cheap I can cut a good 35% off the cost by going AMD. But for most folks the X2 series has enough power that it is frankly overkill. But as always this is my 02c,YMMV
      • Re: (Score:1, Informative)

        by jessedorland (1320611)
        At this point CPU's brands don't matter much, because they are as fast as we need them to be. And OS such as Windows is not fully using all the cores of a CPU -- and most games are not design to benefit duel core or quad core processors.
    • Re: (Score:3, Informative)

      Unfortunately, AMD's "advanced technology" in HT doesn't help them win anywhere but in multi-socket servers. Intel's FSB is plenty sufficient for single socket desktops. So..what's your point again?
      • by gnuman99 (746007)

        Really? Try a Quad core with some memory intensive apps.

        • Re: (Score:3, Interesting)

          by karnal (22275)

          Problem being - if most people don't natively benefit from HT then aside from benchmarks or off-the-wall memory intensive apps, HT wouldn't be that impressive.

          I've had a core2duo 6600 for over a year now - and from what I've been reading, Nehalem isn't really any large performance boost for the typical user over Penryn. Usually I'll buy new CPU/systems when the performance of mainstream games suffer due to the CPU being outdated; in fact, this e6600 is the first system I've had that I've actually upgraded

        • OK. I'll do that. Then you go out and try a quad core showdown between Phenom and C2Q on a smattering of real life applications and tell me who wins. Just kidding - I already know who wins.
      • have all cpus use ht = more chipsets to use with a amd cpu.

  • by Kjella (173770) on Friday August 22, 2008 @08:18PM (#24714087) Homepage

    Nehalem is really the realization of what many slashdotters have claimed before - the typical user doesn't need that much more performance. Both datacenters and laptop users ask for the same thing - power efficiency - and Intel delivers. The Atom is another part of the strategy, even though it's current coupled with a very inefficient chipset.

    The thing is, today we have the knowledge and complexity to fire up kilowatt systems and more - but they're costly running. Certainly there's the extreme hardcore gamers who won't mind running the hottest, most powerhungry quad crossfire system, but they're few and far between. Laptop users think battery life. Desktop users think electricity costs. The result is Nehalem, which promises to deliver a lot more performance per watt.

    If the practise is as good as the theory, AMD is unfortunately in deep shit. They've always been good at delivering ok processors at an ok price, but power efficiency has really only been their strength compared to the Netburst (PIV) processors, not P3 or the Cores. If it amounts to "yeah your processors are cheaper but they cost more to operate" things will fall apart, which is sad since ATI is really doing fine. The 48xx series are kick-ass cards, I just hope they can keep up the competition against Intel...

    • AMD is big on cost and with Intel forcing you to use there chip set it will push costs up where as you can get a AMD 790GX / 780G board with side port ram for about $100 and up lower for boards with out it GeForce board with good on board video are the same price add 4gb of ram for under $100 and get a quad core staring at $150 3 core start at about $100 or a dual start at $50 and you can get a nice for a low cost and a board with 64-128 of board video ram will be good for vista and is better then a intel b

      • by tknd (979052) on Friday August 22, 2008 @09:01PM (#24714347)

        See here [tomshardware.com]

        I know it's a tomshardware article but compared to what people have been posting in silent pc review forums the results are consistent. I do think with a better chipset and laptop style power supply the atom platform can go down to sub 20watts, but for now Intel is not making those boards or even allowing atom platforms to have fancy features like PCI-Express. In fact with the older AMD 690G chipset, some people at silent pc review were able to build sub 30watt systems.

        • by Bert64 (520050)

          The EEE 901 seems to draw somewhat less than 20 watts when running from AC...

    • by DigiShaman (671371) on Friday August 22, 2008 @08:47PM (#24714263) Homepage
      I've always thought that the biggest problem with AMD was the fact their marketing is non-existent. Maybe they should start an "AMD Inside" campaign similar to that of Intel. All I know is that their brand name is fading into oblivion...and fast.
      • Re: (Score:3, Insightful)

        by Pulzar (81031)

        Intel has money to burn, so they can afford prime-time TV commercials... The question is -- is the return on investment worth it? Your average Joe will buy whatever Dell/HP offers them in the right price range. The ones who are looking for a specific CPU are generally informed enough not to be swayed by TV commercials.

    • "The thing is, today we have the knowledge and complexity to fire up kilowatt systems and more - but they're costly running. Certainly there's the extreme hardcore gamers who won't mind running the hottest, most powerhungry quad crossfire system, but they're few and far between."

      I think this is a misinformed statement personally, not intentionally as a slant against you but, gamers are one of the few driving the technology in many key area's of research : World simulation, A.I., etc, "Games" are misnomers f

    • by distantbody (852269) on Saturday August 23, 2008 @01:26AM (#24716001) Journal

      Nehalem is really the realization of what many slashdotters have claimed before... ...power efficiency - and Intel delivers.

      Putting the cringe-worthy PR tone aside (are you connected to intel in any way?), the lowest-clocked 'mainstream desktop' Bloomfield CPU (running at 2.66 GHz, 45nm, quad-core) has a TDP of 130W! Now, efficient or not, that is one hot-and-sweaty processor, making me wonder that if Nehalem truly does have '1.1x~1.25x / 1.2x~2x the single / multi-threaded performance of the latest Penryn ('Yorkfield', 2.66GHz, 45 nm, quad-core, 95W TDP) at the same power level', why wouldn't they let the efficiency gains carry the performance increase of Nehalem for the same TDP?

      Look I may or may not be missing something, but I have been reading plenty of (uncomfortably positive, perhaps bankrolled) material on nehalem, yet I can't shake the perception that, with a huge TDP increase, the return of hyperthreading and the cannibalization of L2 cache for L3 cache, Nehalem seems far more Pentium 4 than Penryn.

      • What you're missing is that the hottest part of the northbridge- the memory controller- is now on the CPU die instead.

    • by Chemisor (97276) on Saturday August 23, 2008 @08:19AM (#24717641)

      > Desktop users think electricity costs.

      Bullshit. The difference between a 130W Nehalem and a 65W Core2 is 65W, which is 11 cents per day (at 7c/kW) or $39/year if you run the computer 24/7. Most people turn the computer off when it's not in use, and 8 hours per day is more likely, or 3 cents per day and maybe $10/year. I'd say the cost is entirely negligible, especially when you compare it to your $80/month Comcast bill.

      • Still. 130W is quite a lot.

        Currently I'm running the following system out of the same wall plug (with a meter inbetween):
        Laptop (desktop replacement actually)
        * 2.0 GHz AMD Turion 64x2
        * 2 WD1200 harddrives
        * 17" monitor

        Additional stuff:
        3 external harddrives in enclosures
        1 external dvd-drive
        1 Wireless router
        1 ADSL modem

        That's drawing a grand total of ... drumroll please: 110 Watts.

        Yes, it's a laptop. But this has more than enough power to do whatever most people would do. Well, it's lacking in the GPU departme

    • by drinkypoo (153816)

      Nehalem is really the realization of what many slashdotters have claimed before - the typical user doesn't need that much more performance. Both datacenters and laptop users ask for the same thing - power efficiency - and Intel delivers.

      They do? I'm still waiting for Intel to deliver quad-core mobile penryn. I couldn't give a fuck about Nehalem unless intel will get their shit together and release mobile at the same time as desktop.

      I'm too lazy, so I'm not going to check right now, but last time I checked the CPU+chipset TDP was better for Athlon 64 than it was for Core 2.

  • Slashdotted (Score:5, Informative)

    by Spatial (1235392) on Friday August 22, 2008 @08:19PM (#24714099)
    The article seems to be down, here's Anandtech's analysis. [anandtech.com]
  • Here we go again (Score:2, Interesting)

    by PingXao (153057)

    Hyperthreading. I thought I was getting an ultra-tech processor when I bought my Dell 8400 some years back, with its 3.2 GHz P4 hyperthreaded power-sucking processor. Once all the reviews and independent technical evaluations and benchmarks were in, it was revealed that outside of a few niche application areas, hyperthreading wasn't all that great.

    It's a good sign Nehalem is also focusing on lowering power usage, the reason Intel had to finally abandon their Tejas plans (the old 8400 Coppermine P4 was a j

    • Re:Here we go again (Score:5, Interesting)

      by Traiano (1044954) on Friday August 22, 2008 @08:58PM (#24714333)
      Don't assume that since Hyper-Threading failed with Netburst that it is forever doomed to fail again. The primary problem with that architecture was that stages along the pipeline didn't support multiple threads. So, any thread context switches forced a flush of Netburst's very, very long pipeline. Intel's next generation of pipelines track multiple threads at all stages and make the prospect of HT much more attractive.
      • Re:Here we go again (Score:4, Interesting)

        by Waffle Iron (339739) on Friday August 22, 2008 @10:42PM (#24714997)

        Hyperthreading can make a lot of sense in some circumstances. Sun pushed hyperthreading to its limits to achieve very impressive energy efficiency for certain niche workloads with its Niagra CPUs and derivatives. (IIRC, up to 128 threads per chip.)

        • Re: (Score:3, Informative)

          by salimma (115327)

          8 threads per core in Niagara 2; you get up to 64 threads, as the chip is available with 4, 6 or 8 cores.

        • Re: (Score:3, Informative)

          by segedunum (883035)

          Sun pushed hyperthreading to its limits to achieve very impressive energy efficiency for certain niche workloads with its Niagra CPUs and derivatives. (IIRC, up to 128 threads per chip.)

          Unfortunately those are very, very, very, very, very niche workloads. Your workloads have to be insanely parallel and each thread very independent of others so that you have little that is blocking. In short, Niagra is just marketing.

    • by tftp (111690) on Friday August 22, 2008 @09:04PM (#24714363) Homepage

      It's really quite amazing how much the hardware has outstripped the ability of software to keep up.

      It's not amazing at all. Most desktop applications are single-threaded because you, the operator, are single-threaded. MS Word could enter words on all 100 pages of your book simultaneously, but you aren't able to produce them. An audio player could decode and play 100 songs to you at the same time, but you want to listen to one song at a time...

      I can see niche desktop applications where multiple threads are of use. For example, GIMP (or Paint.net or Photoshop) could apply your filter to 100 independent squares of the photo if you have 100 cores. However the gain would be tiny, the extra coding labor would be considerable, and you still need to stitch these squares... all to gain a second or two of a rare filter operation?

      The most effective use of multiple cores today is either in servers, or in finite element modeling applications.

      • by Anonymous Coward on Friday August 22, 2008 @09:32PM (#24714563)

        It's not amazing at all. Most desktop applications are single-threaded because you, the operator, are single-threaded....

        That's a pretty simplistic view. Other than the obvious historical reasons, I believe that most applications are single threaded because the languages and tools for writing non-trivial robust multi-threaded applications is lagging far behind the capability to run them.

      • by Mycroft_VIII (572950) on Friday August 22, 2008 @10:32PM (#24714915) Journal
        Games, 3d rendering in general, but games are a big common app that can utilize good multi-threading.
        And multiple cores? Just the O.S. alone runs many things at once, then you've got your drivers, the applications, the widgets, the viruses(hey they're processes too, just because some people have a bit of prejudice:)), the bittorrent running in the background, and the list goes on.

        Mycroft
        • You've trotted out the same old arguments.

          Games are in fact one of the ONLY things on consumer PCs that make heavy use of the hardware. Some people edit video also, or play HD video on their desktop. A small fraction do other 3D tasks. Of course these particular apps can use lots of CPU, but they always have.

          The rest of it is trivial. In case you hadn't noticed, most modern OSes sit there using less than 1% of CPU most of the time. Sure, there are occasionaly bursts of activity but these are rare and usual

          • Oh I wasn't arguing necessary, just usefull and more efficient to have multiple threads running at the same time.
            And modern gpu's can help a lot with some of those tasks.
            I probably should have pointed out my own perspective might be a tad skewed as I run 3d rendering apps (well poser mostly) than can easilly peg all four cores and slam my ram, so naturally I'm all for bigger,better,faster,cheaper in computers.
            Besides look at the laser, it was a solution looking
      • For example, GIMP (or Paint.net or Photoshop) could apply your filter to 100 independent squares of the photo

        I think GIMP does. On my machine, it's been using more than 100% of one core according to top. Anyone else noticed this with recent versions? And if you're editing 250MPix images, it makes a big difference.

      • one core for the mouse, one core for the display, no, make that two. Two cores for the s/ata and four cores for the USB3.

        That's the monkey goes, ...

      • by TheRaven64 (641858) on Saturday August 23, 2008 @07:32AM (#24717451) Journal

        It's not amazing at all. Most desktop applications are single-threaded because you, the operator, are single-threaded. MS Word could enter words on all 100 pages of your book simultaneously, but you aren't able to produce them.

        Absolute nonsense. Most applications have inherently parallel workloads that are implemented in sequential code because context switching on x86 is painfully expensive.

        Consider your example of a word processor. It takes a stream of characters and commands. It runs a spelling, and possibly grammar, checker in the background. It runs a layout and pagination algorithm. Both of these can also be subdivided into parallel tasks. If you insert an image, it has to decode the image in the background. Then we get to the UI, updating the view of the document via scrolling and so on while the model is not modified.

        • Re: (Score:3, Informative)

          by amorsen (7485)

          Most applications have inherently parallel workloads that are implemented in sequential code because context switching on x86 is painfully expensive.

          Context switching on x86 is dead cheap. It's probably the cheapest of all general purpose architectures available right now. We're talking a few hundred cycles cheap. Only the P4 is a bit behind, and Nehalem makes things faster, to the point where Intel almost catches up with AMD.

          Windows manages to make process switches a lot more expensive than necessary, but thread switching isn't bad. With Linux it hardly matters whether you switch processes or threads, they're both fast.

          • Compare it to SPARC, or any other modern architecture with a tagged TLB. On x86, a context switch (between processes - threads don't do a full context switch) requires a TLB flush, which means that the next few hundred memory accesses will all involve a TLB miss, which means that they will require the CPU to walk the page tables. On SPARC, it requires updating the context ID register. A SPARC context switch has about the same cost as a function call. ARMv6 and later have a similar model.

            A lot of the

            • by amorsen (7485)

              On x86, a context switch (between processes - threads don't do a full context switch) requires a TLB flush, which means that the next few hundred memory accesses will all involve a TLB miss, which means that they will require the CPU to walk the page tables.

              That's what software thinks is happening. However, on x86 the hardware is responsible for the page tables, so it tags the TLB entries behind the scenes.

              On SPARC, it requires updating the context ID register. A SPARC context switch has about the same cost as a function call.

              A SPARC context switch has to save all the damn registers. All 192 of them or however many they have these days. Even if it's just a thread switch. Probably twice. Function calls get away with moving the register window, which is a lot faster.

      • by maraist (68387) *

        Being an enterprise multi-threaded programmer, I'm going to beg to differ.. The reason being that people THINK single-threaded when they program - I know because I've had to retrain lots of entry-level programmers who give little/no thought to race-conditions, synchronized routines.

        But also in this MT environment, there is a LOT that a trivial text-editor can be doing in the background.. The more complex the task you are performing, the more real-time analyzers can be thought up by trivial-editor writers.

        Ta

        • Re: (Score:3, Interesting)

          Take MS word.. You have grammer checking, but what about background googling to do FACT checking.

          Exactly. There's a million things that a "simple" program like Word could do; instead, they just add on cosmetic crap that slows the program down. I haven't seen a significant advancement -- something that made the old program obsolete -- in Word in a decade.

          As one example of a pathetic feature, Word has an option to "compare two documents". In theory, this would be a useful feature when someone extensively edits a document and hands it back to you. In reality, it's completely useless. If you take a d

      • Actually, we are multithreaded. We have several billion neurons in our brain,. most of which operate independently. I don't have to stop typing or talking to breathe, regulate my heartbeat or body temperature. I can read your posting while drinking my morning coffee. And while all of this is going on, I can listen to my .mp3s

        But it would be totally cool if I could get a brain upgrade that would allow me to think about several problems at once, even if I only have two hands to type. Eventually, I would

      • Like hell Word should be single threaded. Sure, I can only type one letter at a time, but word has to repaginate, check spelling and grammar, and render the page so I can see it. Not that Word isn't usually sufficiently fast at them; at least until I turn on Endnote. Then it takes about 2 minutes to add a single reference to a 40 page proposal.
    • Re:Here we go again (Score:5, Informative)

      by JorDan Clock (664877) <jordanclock@gmail.com> on Friday August 22, 2008 @09:15PM (#24714453)
      After reading the overview from Anandtech, it has been revealed that Hyper-Threading is far more efficient on Nehalem than any P4 could have hoped to be. It has better cache, better access to memory, and is a much wider core. Hyper-Threading also allows Nehalem to do more with each clock. I highly suggest reading Anandtech's breakdown of Nehalem. It is very comprehensive and does a great job of explaining things in quite a fine grain of detail.
    • Re: (Score:2, Interesting)

      by Anonymous Coward
      The Nehalem architecture is designed to maximize performance for a given power level. If you happen to be running a legacy application which cannot take advantage of all the cores then the unused cores will go into a low power state and the cores in use will overclock until the selected power envelope is reached.

      I, for one, welcome our new automatic overclocking overlords.
  • how much is enough? (Score:5, Informative)

    by Tumbleweed (3706) * on Friday August 22, 2008 @08:59PM (#24714341)

    At this point, as long as I can watch HD video without any noticeable slowdowns, I'm good. A GPU or integrated video solution that can do that plus some energy efficient CPU is really all I'm interested now. The software issues with the 4500HD are disappointing, but hopefully it's *just* a software issue this time, and can be fixed soon enough.

    Then again, that's just me; I'm not a gamer or video editor.

    • so pretty much your saying since you do stuff that can be done with relatively old hardware, there should be no more upgrading for more abilities?

    • It's just that software does not keep up with hardware advances. There are many semi-ai or ai things I would have running on my PC. Classical example is indexing images or videos. Being able to query "show me all pictures where my girlfriend wields watch on her left hand" etc.

      My favorite would be a robot which will clean up my house. Not just hoover or clean up a floor. Also, clean up higher standing things, recognize what is a useful thing, what is a piece of rubbish and what I should decide if it should

  • Gene pool comment (Score:3, Interesting)

    by blahplusplus (757119) on Friday August 22, 2008 @09:14PM (#24714447)

    "completely new architecture either. Intel representatives disclosed that Nehalem 'shares a significant portion of the P6 gene pool,"

    That's like saying equations share a significant portion of numbers gene pool. It's all geometry when you get down to it. I mean really, there are going to be certain circuit geometries that are always good to use and whom you can't totally get away from.

    • by AcidPenguin9873 (911493) on Friday August 22, 2008 @11:34PM (#24715361)

      I'm not sure what you mean by geometries. SRAM arrays, flops, random logic, carry-lookahead adders, Wallace-tree multipliers (building blocks of processors) generally look similar across all high-performance ASICs over the past 15 years. Circuit geometries themselves have almost certainly changed completely since P6 days - 45nm is a hell of a lot smaller than 350nm, and the rules governing how close things can be have almost certainly changed.

      I think what the article really means is that Nehalem shares a lot of the architectural concepts and style of the P6: similar number of pipe stages, similar number of execution units, similar decode/dispatch/execute/retire width (I think Core 2/Penryn/Nehalem are 4 and P6 was 3), similar microcode, etc. Of course enhancements and improvements have been made in things like the branch predictor, load-store unit, and obviously the interconnect/bus...but if you look at Nehalem closely enough, and indeed if you look at Pentium M, Core 2, Penryn too, you can see the architecture of the P6 as an ancestor.

      • "I'm not sure what you mean by geometries."

        In terms of existent structure, surface, or energy, what isn't geometry? What isn't a shape that has existent structure and can be detected?

        If you can't answer that, then you'll know :)

      • To put it another way, when we detect something we detect a surface partially or wholly, and if it's a surface, it has structure, and if it has structure it is... geometry!

        If you feel I am incorrect please point out where I made the error.

  • Given how closely Apple has worked with Intel before and after the processor switch from PowerPC, I wonder how much more Hyper-Threading aware OS X 10.6 (AKA Snow Leopard) will be? After all, it's supposed to be a "tuning" release focused on full 64 bit performance across the OS, so it wouldn't surprise me to see OS X 10.6 to see much greater speed gains from HT than Vista on Nehalem, especially given Anandtech's description of how Vista screws up Turbo mode [anandtech.com] on Penryn-based systems. (And of course, MS won't go back and put hyperthreading awareness in XP at all...)

    • Given how closely Apple has worked with Intel before and after the processor switch from PowerPC, I wonder how much more Hyper-Threading aware OS X 10.6 (AKA Snow Leopard) will be?

      I don't think an operating system actually needs very much support for Hyperthreading.

      Of course the OS needs to know about Hyperthreading and not schedule two threads to run on the same core while any other core is completely unused (so hyperthreading would only be used if number of running threads > number of cores). And if different threads have different priorities, you would want to use hyperthreading for threads with low priority and use a full core for a thread with higher priority. If the OS gi

      • Re: (Score:3, Informative)

        by TheRaven64 (641858)
        Actually, scheduling for SMT can be very difficult or very easy, depending on the architecture. Something like the Niagara is easy to schedule for - every context basically gets 1/8th of the CPU, the decoder just issues one instruction from each in turn. In more fine-grained implementations you have one thread running and another thread getting to use the execution units when the first one isn't (e.g. if the first one is issuing a load of floating point operations and the other thread has an integer opera
  • Isn't that one of the books of Mormon?

    • by MPAB (1074440)

      Of MORe MONey for Intel, perhaps.

    • Re: (Score:2, Interesting)

      by Perf (14203)

      Nah, it's named after a river in Oregon, which in turn, is named after a Native American tribe.

  • by Louis Savain (65843) on Friday August 22, 2008 @10:18PM (#24714805) Homepage

    More than any other organization, Intel knows that multithreading is bad. Lots of smart people such as professor Edward Lee [berkeley.edu] (the head of U.C. Berkeley's Parallel Computing Lab) have warned Intel of the disaster down the road. It is time for Intel and everybody else to make a clean break with the old stuff. There is an infinitely better way to design and program parallel computers that does not involve the use of threads at all. Instead of the Penryn, Intel should have picked something similar to the Itanium, which has a superscalar architecture [wikipedia.org]. A sequential (scalar) core has no business doing anything in a parallel multicore processor. Intel will regret this. Sooner or later, a competitor will read the writings on the wall and do things right. Intel and the others will be left holding an empty bag. To find out the right way to design a multicore processor, read Transforming the TILE64 into a Kick-Ass Parallel Machine [blogspot.com].

    • Re: (Score:1, Insightful)

      by Anonymous Coward

      Yeah, that's what Intel thought as well, ten years ago. Many valuable lessons were learnt.
      They're still continuing the Itanium line, I'd guess primarily for the research value and to save face, but I don't think they're particularly eager to face the ridicule they'd get from committing all their mistakes a second time.

      • by Bert64 (520050)

        Well, Itanium was a good idea, and getting away from the legacy cruft of x86 would be a good thing, but in this case competition and closed source software are stifling progress...

        Competition because people won't migrate until there is a clear cut case to do so, or they are forced... Apple were able to transition their users from m68k to ppc and then to x86 because there was no other way forward... Had a third party been producing clones, people would have chosen the path of least resistance and stuck with

    • Re: (Score:2, Interesting)

      by paradigm82 (959074)

      Intel's CPU's have been superscalar since P6 (Pentium Pro). They can execute 3-4 instructions per clock under optimal conditions (yes all the way through the pipeline). They have out-of-order execution, speculative execution, register renaming etc. However, there's a limit to how much you can execute in parallel at the instruction level.

      Could you elaborate on what Intel's CPU's are missing and what Edward Lee was warning about?

      • Perhaps the GP should have included a link to "The Problem with Threads" by Edward A. Lee, IEEE Computer, 39(5):33-42, May 2006, also available here [berkeley.edu] as Electrical Engineering and Computer Sciences University of California at Berkeley Technical Report No. UCB/EECS-2006-1 .
  • ECC? (Score:1, Insightful)

    by Anonymous Coward

    Now that the memory controller will be in the CPU, does that mean they'll enable ECC RAM support for their consumer-level systems, the same way most AMD boards do?

    The idea of using 4GB or more with no error correction just doesn't interest me.

    • Nope; they'll find some way to save a few cents by disabling ECC. If Intel doesn't cripple it the BIOSes will.

  • by sam0737 (648914) <samNO@SPAMchowchi.com> on Saturday August 23, 2008 @01:00AM (#24715845)

    The QuickPath sounds so like AMD's HyperTransport. 3 pairs per CPU, integrated controller is exactly what AMD's doing for long long time.

    20-bit wide 25.6 GB/s per link? HyperTransport is already capable at deliverying 41.6 GB/s per link in 2006. (according to Wikipedia)

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