Talk:Multi-core processor

Dual Core, Quad Core, Eight Core, etc.

Could we perhaps make some new entries listing applications that can run on different amounts of cores? Example: list all modern apps that can run on 4 cores... list apps that can utilize 8 cores... etc. Jacobhaines (talk) 20:21, 4 November 2009 (UTC)

Technically, all programs can use more then one processing unit, provided they use more then one thread at any one point in time. A lot depends on how (or if) the OS assigns programs across multiple processing units. For that reason, answering you question is nigh impossible, although a few examples of good threaded programs do exist [Prime95 and other number-crunching programs are prime examples] --Gamerk2 (talk) 18:50, 24 February 2010 (UTC)

Defragmenting and antivirus are not CPU intensive operations

They are I/O intensive and as such, do not benefit from a multicore CPU. —Preceding unsigned comment added by 77.70.95.214 (talk) 19:32, 8 February 2008 (UTC)

Advantages: CPU-bound, IO-bound, Memory bound

From the "Advantages" section:

The largest boost in performance will likely be noticed in improved response time while running CPU-intensive processes, like antivirus scans, ripping/burning media (requiring file conversion), or searching for folders.

Aren't anti-virus scans and searching for folders usually IO-bound not processor-bound? Perhaps audio & video processing and 3D rendering would be better examples. Burning media would be IO-bound too, so the conversion stage of ripping media is the only CPU-bound example left (and it counts as "audio & video processing"). —tedp (talk) 21:35, 5 June 2009 (UTC)

Would someone explain in the article how external memory (non-cache) memory is treated and used by the processors. I realize this is operating system dependent, but someone familiar with this in a Windows, Linux envrionment please explain. If there is another wiki that describes this could someone put a link to it?

Put simply, this means that signals between different CPUs travel shorter distances, and therefore those signals degrade less

I do not think signal degradation is the limiting factor based on distance, but rather propagation delay. Signal degradation, as far as I can tell, is only an issue over much larger distances. —Preceding unsigned comment added by 66.41.255.4 (talk) 17:21, 19 March 2011 (UTC)

Disadvantages: yield issues

Intel's approach (2 dies in a package) is mentioned. AMD's approach to yield problems, by binning and converting quadcores with a single failed core to triple cores could be mentioned. —Preceding unsigned comment added by 81.6.232.208 (talk) 09:52, 6 January 2010 (UTC)

Multi-core versus Multicore

This may be a non-issue, but it seems that multicore is becoming the more popular spelling for multi-core/CMP machines. 68.34.101.214 (talk) 15:01, 22 March 2008 (UTC)

From: Manasa Rokobari —Preceding unsigned comment added by 210.7.2.119 (talk) 21:31, 1 September 2008 (UTC)

Jargon and encyclopedias

Given that this is supposed to be an encyclopedia for non-initiates to find info on various topics, is possible to keep the jargon to a minimum? I was interested in knowing precisely what dual core processors were, but I found little that was comprehensible on this particular page. A one-paragraph, jargon-free definition could perhaps be added at the top of this article. Thanks! Episteme1972 —Preceding unsigned comment added by Episteme1972 (talk • contribs) 17:54, April 3, 2008

ps3?

You mention the xbox, doesn't the ps3 have more?

It does. Xenon has 3 cores, Cell have 9. -- Henriok (talk) 13:19, 18 June 2008 (UTC)

The cell has seven cores, and they are actually SPEs, not cores. It would be more accurately to remove the playstation 3 as an example of multi-core because it is atypical. --Colostomyexplosion (talk) 14:01, 31 July 2008 (UTC)

The Cell has 9 cores, and even though it is atypical, it's still 9 cores. Even if the Cell in PS3 have one disabled in manufacturing and one out of bounds for homebew, it's still 9 cores. The eight SPEs have their own pipeline, local memory, registers and ISA. They are cores and because it's atypical it'd be a nice example here. -- Henriok (talk) 21:16, 21 August 2008 (UTC)

The Cell has 8 SPEs (or cores if you like), not nine. One is disabled, and one is used for the OS, that makes seven SPEs or which 6 are accessible to commercial and homebrew applications. Colostomyexplosion (talk) 13:50, 22 September 2008 (UTC) From: Manasa Rokobari Samuraki —Preceding unsigned comment added by 210.7.2.119 (talk) 21:34, 1 September 2008 (UTC)

The Cell has nine cores, eight SPEs and one PPE. -- Henriok (talk) 23:17, 18 October 2008 (UTC)

Commercial examples - cleanup

I'm going to attempt to clean up the commercial examples section, but there are a lot of dubious entries in there. Firstly, is a general purpose microprocessor and a DSP on the same die a multicore processor? I don't believe so, and I will remove them if there are no objections. Secondly, do we need to list every single embedded multicore processor in existence? Since they are more common than hydrogen atoms, I suggest that only those with proven notability (eg. novel design - hundreds of cores, significant market presence, exceptional application) should be included, since a lot of the entries sound like advertisements to me. Thirdly, I think there should be some brief info for each entry on why the processor is notable. What do you think? Rilak (talk) 05:55, 5 June 2008 (UTC)

Sound good. I agree -- Henriok (talk) 13:27, 18 June 2008 (UTC)

If you look at the edit history, I've already started and have removed a few entries. I'll try and get the list coherently ordered soon. Does ordering the entries alphabetically and maintaining a coherent format (eg. MyCorp MyCores, a 24-core MIPS processor) sound good to you? Rilak (talk) 05:54, 19 June 2008 (UTC)

I've deleted a few entries such as the Diopsis, as it seems to be a DSP and a CPU stuck on the same die, and the Infineon IP phone processor, as it seems to be a DSP stuck with something else (microcontroller?). I've also begun sorting the entries in alphabetical order, with the name of the company first, followed by the name of the product. It would also be helpful it someone updated the AMD and Intel entries, some of the information seems a bit old. Rilak (talk) 10:23, 22 June 2008 (UTC)

The cleanup is complete. A few entries got axed, primarily the Freescale PowerPC softcores. I do not feel that these are actual "examples" as they are generally ordered by customers to integrate into their own products. Also axed were entries that did not describe any actual "examples", but companies/people that design/fab multicore processors as part of their business. Unless actual examples are provided, I think that such entries should not be included as they are too vague. Finally, the software examples section looks like that it is infested with advertising. Most of the links are external, suggesting that the entries are there to promote a product rather than to describe one. If they are indeed notable, they should link to a Wikipedia article. I'm not knowledgeable about this subject, so I won't remove any content, but I think that a cleanup of the section is warranted. Rilak (talk) 12:08, 28 June 2008 (UTC)

I have added picoChip to the listing. I think it is legitmate on two grounds: a) It is described in the text earlier, so should be in the list b) With 200-300 cores per chip, it would pass Rilak's criteria above("novel design - hundreds of cores")

Trust that is acceptable. Rupert baines (talk) 11:42, 9 September 2008 (UTC)

I really appreciate the cleanup Rilak has done.

I think that a DSP and a general-purpose CPU on the same die *is* a 2 core chip, and therefore a multicore chip. You have a DSP core, and a CPU core, that's 2 cores -- I'm puzzled as to why anyone would think 2 cores is not multicore. However, I agree that there are so many 2 core chips that there is not room in this article to list more than a few of the most especially notable 2 core chips.

Ordering the entries alphabetically by manufacturer is much better than the previous no order at all.

I would prefer ordering the entries by number of cores (most-cores-first). That number is an important characteristic of a chip. The position in the alphabet of the name of its manufacturer -- not so important, in my opinion. I think any chip that has so many cores that it places near the top is inherently notable enough to add, while a chip that has so few cores that it is #20 or below on such a list would need some other reason to make it important enough to add.

Would you mind if I or someone else re-sort the "hardware" list by "number of cores" first, company name second, product name third? --68.0.124.33 (talk) 22:23, 10 September 2008 (UTC)

It is nice to thanked for work I've done on Wikipedia, thank you. Regarding DSPs and general purpose processors on the same die, I have to ask, does the general purpose processor and the DSP perform multiprocessing? If I understood correctly, the cores must be perform multiprocessing in order to be classified as multicore, otherwise, the processors are just integrated on the same die, which has been done for a long time. As for sorting the list by the number of cores, can you elaborate as to why more cores would inherently mean more notability? Rilak (talk) 08:03, 11 September 2008 (UTC)

Wholly agree - a good job and deserves thanks.

I'd agree with Rilak that 2 different cores (eg OMAP with a DSP and a GPP) is not "multi-core" in the sense we use it here. The principle here (and maybe it should be cleaere?) is that there is some single architecture, with tasks being adddressed by several cores together. Merely having several processors in one system, doing things independently, is not the same thing - even if they are on one die. Maybe we should put a para saying this?

I'm wary of listing by number of cores, as too many other vaiables eg the type of core is not the same. "Should we list by 64 bit first, then 32-bit...". If item#20 had fifty 64-bit cores that should score "higher" than item#19 who had sixty 8-bit cores: more cores is not the same as "notable" -- but this gets us into value judgements.

(To declare an interest: I work for picoChip. In a biassed way perhaps I ought to that, as with 300 cores we'd do better than 'p' -- but I think it is the wrong thing to do.)

Alphabetical is neutral, non-judgemental and in-line with encyclopaedia style Rupert baines (talk) 08:55, 11 September 2008 (UTC)

A paragraph for explaining that all the cores have to be the same architecture, with tasks being processes by multiple cores is a good idea. I might draft a paragraph when I've found some sources. In regards to how the list should be ordered, I could not have said it any better than Rupert baines - ordering the list alphabetically is neutral and more suited to an encyclopedia. Rilak (talk) 06:59, 13 September 2008 (UTC)

"encyclopaedia style"? Dear reader, you may be surprised to learn that "passive voice" and other common style features of previous encyclopedias are discouraged at Wikipedia (Wikipedia:AWW). We Wikipedians think we can do things better :-). I agree that alphabetical order is neutral and non-judgmental, and therefore should be used unless there is something better. However, I was surprised to learn that none of the example lists in the current version of the relevant Wikipedia style guideline -- Wikipedia:Embedded list -- are in alphabetical order.

Other Wikipedia articles where editors have decided that biggest-number-first is "more suited to an encyclopedia" than alphabetical include (in no particular order) continent, high jump, list of highest mountains, list of tallest buildings and structures in the world, shortwave, slow-scan television#Frequencies, miniaturized satellite, additionally guyed tower, partially guyed tower, and list of catastrophic collapses of radio masts and towers.

Sorting by number of cores has the advantage of making it easier (than alphabetical) for our readers to find the most cores on one chip, the most 32-bit cores on one chip, which number-of-cores are particularly popular ("is 16 cores more popular than 10 cores?"), etc. The number of cores on a particular chip is an objective, verifiable fact that everyone agrees on and is therefore neutral. Except for the "number of cores in a Cell" controversy :-). --68.0.124.33 (talk) 04:21, 17 September 2008 (UTC)

The problem with the other examples you cite is that the units are consistent and there is no ambiguity on what is "more". In contract, "core" is quite an elastic term: this list encompasses everything from 8 bit cores to 64 bit . As such, I'm not sure that on its own it can answer the questions you raise. Ideally we'd have a table with some dynamic code so you can sort as you need to, but... Maybe some text, describing trends and the notable highlights? Rupert baines (talk) 13:41, 17 September 2008 (UTC)

One option would be a sortable table; then the reader could choose which attribute they wish to sort by. See Help:Sorting. Dcoetzee 14:30, 18 January 2009 (UTC)

But the section is currently not a comparison of multicore microprocessors, it is merely a list of examples. I am not convinced of the value of changing the scope of that section due to the impossibility of a proper comparison as others have said before. Rilak (talk) 05:44, 20 January 2009 (UTC)

I cleaned up the Intel Polaris timeframe from the original relative "5 years" to the absolute announced time of 2011, shout this chip be removed from commercial to a new PROTOTYPE section?

Core?

What is a core? The fist mentioning of the word "core" is on the first line in this article and it points to a disambiguation page, core. This is not good. There should be an article describing a processor core, and it should not redirect to this article. -- Henriok (talk) 13:31, 18 June 2008 (UTC)

I agree. The disambiguation for "core" does not define what it is. Rilak (talk) 05:56, 19 June 2008 (UTC)

I also agree. Too many readers are left wondering, "What is a core?" In particular, several well-meaning Wikipedians on this talk page disagree on whether a DSP CPU + general-purpose CPU combo chip counts as "multi-core".

I would prefer some crisp, objective definition, so that it's obvious to everyone whether a particular chip counts as a "multicore" under the particular definition we use on this page, rather than a vague, ambiguous definition -- such as "It's a multicore if its marketing person says it's multicore".

The article "Running Queries On Multi-Core Processors" by Joe Duffy and Ed Essey, MSDN Magazine 2007, claims that

"Once pervasive mainly in servers and desktop PCs, now multi-core processors are being used in mobile phones and PDAs, resulting in great benefits in power consumption."

Does that refer to the "DSP CPU + general-purpose CPU combo" referred to above -- or is there some other kind of multi-core used in mobile phones and PDAs in 2007 ?

The article "CPU designers debate multi-core future" by Rick Merritt, EE Times 2008, claims that

"Chuck Moore... suggested computers should be more like cellphones, using a variety of specialty cores to run modular software scheduled by a high-level applications programming interface.

... Atsushi Hasegawa, a senior chief engineer at Renesas, generally agreed. He suggested the cellphone's use of many specialty cores working in concert is a good model for future multi-core designs.

... Anant Agarwal, founder and chief executive of startup Tilera, took the opposing view. He said multi-core chips need to be homogenous collections of general-purpose cores to keep the software model simple. ..."

Is Anant Agarwal, who I respect as an expert in this area, insisting that multi-core must be defined as homogenous collections of general-purpose cores, which seems to exclude the Cell processor? --68.0.124.33 (talk) 04:52, 17 September 2008 (UTC)

I do not think that a DSP and a general-purpose processor on the same die can be categorized as "multicore".

IBM, the first company to offer a commercial dual-core server microprocessor, the POWER4, referred to their design as a "chip multiprocessing" or "CMP" design. The main characteristic of CMP is that there are two or more processors on one die performing symmetric multiprocessing to exploit thread level parallelism in order to achieve high performance. Later, when the term "multicore" became more prevalent, it replaced the term "CMP" and IBM began to refer to later revisions of the POWER4 as a "multicore" microprocessor.

The "multicore" microprocessors with a DSP and general-purpose processor on the same die, from some examples I have seen, do not perform symmetric multiprocessing. The relation of the DSP and the general-purpose microprocessor is similar to that of a coprocessor, to the extent that some designs had the general-purpose processor communicate with the DSP through an on-die peripheral bus! I have no references at the moment though. Rilak (talk) 09:23, 17 September 2008 (UTC)

How about we just add this as a discussion? We could have a section on (say), "Definition" and cover this there. I think that Chuck Moore & Anant Agarwal are important enough to reference there different opinions, and it does provide a sensible place for discussion on heterogenous / homegenous. Rupert baines (talk) 13:33, 17 September 2008 (UTC)

I made this discussion an entry with in 'Architecture' and included the EE Times discussion: Moore & Agarwal are notable enough to be included as commentary.Rupert baines (talk) 12:37, 30 September 2008 (UTC)

Multiple "Chuck Moore"s (Forth vs AMD)

Of note, this article references both the chief engineer at AMD named Chuck Moore, and the designer of the Forth language and the Intellasys SEAforth multicore chip, Chuck Moore. The EE Times discussion section of this article incorrectly links to the latter on Wikipedia when it's about the former. --64.58.22.201 (talk) 20:24, 27 March 2009 (UTC)

Oops, my mistake. I didn't realize there was more than one CPU designer with that name. Now that I'm looking, I see lots of them -- including Chuck, Charles, Gordon, and Calvin. --68.0.124.33 (talk) 02:29, 6 April 2009 (UTC)

Fixed - I removed the link. Guy Harris (talk) 08:36, 19 February 2011 (UTC)

page is a little too PC centric

the page isn't objective and isn't platform neutral, and it gives almost no technical insight besides being a advertisement for users how great multi-core is, and then pointing out negatives which aren't actually negative for multi-core systems. Markthemac (talk) 20:35, 14 July 2008 (UTC)

Could you point out what is exactly wrong with the article? Specific paragraphs, sentences, statements, that sort of thing? Rilak (talk) 07:39, 15 July 2008 (UTC)

point:1 In order to continue delivering regular performance improvements for general-purpose processors, manufacturers such as Intel and AMD have turned to multi-core designs, sacrificing lower manufacturing costs for higher performance in some applications and systems. 2

for example the American PC game developer Valve Corporation has stated that it will use multi core optimizations for the next version of its Source engine, shipped with Half-Life 2: Episode Two, the next installment of its Half-Life series.[2][3], and Crytek is developing similar technologies for CryEngine 2, which powers their game, Crysis. Emergent Game Technologies' Gamebryo engine includes their Floodgate technology[4] which simplifies multicore development across game platforms. See Dynamic Acceleration Technology for the Santa Rosa platform for an example of a technique to improve single-thread performance on dual-core processors. Markthemac (talk) 18:07, 20 July 2008 (UTC)

and i think u can read more yourself, games etc are really only interesting for gamers and not developers or anyone really interested in multi-core development and reasons behind certain processes. Markthemac (talk)

I 'promoted' the section on Embedded to make this distinction clearer (it was a subhead of software which is not the whole part of thing). I also added a section there discussing the differnce in development as a significant impact on markets (eg less need to support legacy code or ISVs) Rupert baines (talk) 11:44, 9 September 2008 (UTC)

Out of the entire article, I only found one paragraph, the one you quoted, that deals specifically with computer games. I don't see how this makes the article bias in any way, especially when there is an entire section, approximately one and a half pages long that deals with development and software on multicore processors and licencing for high-end data center and technical applications. The paragraph which you claim is bias has full justification for being in this article - computer games have a major role driving the development of hardware, and it has been doing so since the late 1990s. If the article ignored the application of multicore to consumer and entertainment systems (all modern video game console processors - Broadway, Cell, Xenon are multicore), then the article would be truly biased and misleading as it is promoting a one sided view of the concept. Rilak (talk) 06:46, 21 July 2008 (UTC)

At some point many multi-cored cpus will include cores of various functions... floating point... sound... etc... —Preceding unsigned comment added by Johnk119 (talk • contribs) 17:09, 27 October 2008 (UTC)

merge

I suggest merging "manycore processing unit" into "multi-core". They look like the same thing to me. --68.0.124.33 (talk) 22:38, 10 September 2008 (UTC)

completely agree. "many-core" is a useful distinction in that it describes a subset of multicore, but the two are closely related and most of the discussion here actually does address many-core.

How best to do this? many-core redirects here? We retitle the page "multicore (and manycore)" ? Rupert baines (talk) 08:38, 11 September 2008 (UTC)

Well, "manycore" is just a term used to describe a particular type of multicore microprocessor, so the definition of manycore should be mentioned in the lead of this article, and the manycore article should be turned into a redirect. The current manycore article is mostly a definition at the moment anyways, with some opinionated statements about scalability and the position of manycore, so I don't think this will be problematic. Rilak (talk) 08:53, 11 September 2008 (UTC)

Many-core should be a section of the multi-core page. Cocoaguy ここがいい_contribs^talk Review Me! 22:03, 22 September 2008 (UTC)

I added this as a para in 'Definition'. Most of the body does discuss many-core as it is.Rupert baines (talk) 12:37, 30 September 2008 (UTC)

I Charles Elliot Keisler Agree with ths dicision the many-core article is small and contains no where near the amount of data that coloud be explaind by merging with the Multi-core Page --Koman90 (talk) 19:21, 9 October 2008 (UTC)

I have redirected many-core to this article now. henrik•talk 17:14, 29 October 2008 (UTC)

First paragraph

The first paragraph of the article is a bit long and could ease a little clean up. Perhaps we should break it into two or more paragraphs? Either way, I found one sentence particularly confusing. Can anyone decipher this:

The most commercially significant (or at least the most 'obvious') multi-core processors are those used in personal computers (primarily from Intel and AMD) and game consoles (e.g., the eight-core Cell processor in the PS3 and the three-core Xenon processor in the Xbox 360).

76.22.72.163 (talk) 09:22, 18 January 2009 (UTC)

I agree the intro was pretty choppy. I re-wrote it and there haven't been any complaints (yet) so I removed the "intro-rewrite" template. MBbjv (talk) 02:18, 3 June 2009 (UTC)

Why only commercial chips?

The current organization of example chips with the major heading "Commercial examples" seems non-optimal to me since there are few non-commercial chip examples and they probably don't deserve their own major section. Any objections to organizing "Hardware" and "Software" as major headings with "Commercial" and "Research" as sub-headings? BTW, the Univ of Maryland ref does not appear to belong here in my opinion. MBbjv (talk) 04:20, 3 May 2009 (UTC)

Since there were no objections, I made the changes. MBbjv (talk) 02:11, 28 May 2009 (UTC)

greek and latin prefixes for multicore - why afraid of consistent naming in english realm?

so we have dual and quad core cpus these days, but not sexa-cores. all of a sudden we jump from latin to greek naming and we have hexa-cores instead. so why didnt we have di- and tetra-cores then instead in the first place? is this some means to avoid the sex(a)- prefix in the english realm? too many people and too many closeminded folks all over this planet? also read: http://www.brightsideofnews.com/news/2009/8/25/intel-to-demonstrate-a-32nm-core-i9-cpu-in-september.aspx —Preceding unsigned comment added by Suggestednickname (talk • contribs) 06:49, 27 August 2009 (UTC)

Article title

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was page moved. ukexpat (talk) 03:27, 3 December 2009 (UTC)

---

Multi-core → Multi-core processor — WP:NAME says to use nouns and noun phrases rather than adjectives. Nurg (talk) 22:02, 1 December 2009 (UTC)

• Support makes sense. --Labattblueboy (talk) 04:04, 2 December 2009 (UTC)
• Support: Clearly the correct name per WP:NAME - seems non-controversial to me. If no objections in the next few hours, I'll do it. – ukexpat (talk) 17:01, 2 December 2009 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Couple of points...

• I think the list of examples is too long and may be unnecessary, possibly spammy.
• There are too many external links, and it is in danger of becoming a WP:LINKFARM. – ukexpat (talk) 03:30, 3 December 2009 (UTC)

Plagiarism?

Unless Ian Foster is the author of this Wiki article, at least some portions have been plagiarized. Under Software Impact, the section about Partitioning, Communication, etc. were extracted word for word from here: http://www.mcs.anl.gov/~itf/dbpp/text/node16.html Jif101 (talk) 20:53, 10 December 2009 (UTC)

But how fast is it?

The thing that no one seems to want to tell me is this: If a dual- or quad-core CPU is listed, they'll say it's 3.6Ghz. Now, does that mean that the effective speed of the whole thing is two or four times that? So if I buy a dual-core 1.8Ghz, am I really getting 3.6 overall? I mean, obviously there's threading issues that would prevent this, but I'm sure you know what I'm asking. Is the listed speed the overall speed or speed per core? Is there no real speed increase for multiple cores, and really just an efficiency increase? I'm very confused. --Buddy13 (talk) 19:04, 26 December 2009 (UTC)

No. If you have a Quad running at 2.5GHz, you have four processing units, each running at a speed of 2.5GHz. While you have a total of 10GHz of processing power (assuming 100% scaling across CPUs), no individual unit can go faster then 2.5GHz. If you have a non-threaded program that runs on a single core, running on a 2.5GHz single core will provide the same exact speed as a 2.5GHz dual-core and a 2.5GHz Quad, because the extra cores are not used. --Gamerk2 (talk) 19:04, 24 February 2010 (UTC)

I was also wondering this. I suspect that many people who come here are researching CPUs with the intent of buying, so I think it would be of great help if we added in a section describing how to compare processors, such as discussing the benefits of dual core 2.5 ghz vs quad core 1.6 ghz and the different kinds and values of cache. This would essentially be a discussion of end-user useability and would totally be appropriate, IMO. Khono (talk) 11:26, 10 April 2010 (UTC)

A change might be in order

Sorry -- I'm not a "top expert" on this by a long shot but the following line hit me as a bit off-the-mark.

A many-core processor is one in which the number of cores is large enough that traditional multi-processor techniques are no longer efficient — this threshold is somewhere in the range of several tens of cores — and probably requires a network on chip.

The distinction between 'multi' and 'many' is the same as 'some' and 'a lot'. It's just more cores with no really clear line defining a break point -- I've yet to see one stated. Having something about many vs multi (parent to child style) is good but not as the start of the sentence it is in.

Outside of some SoC attempts, many-core systems are being implemented as multiple multi-core processors -- as in successors to single-core processors by multi-core in multi-processor systems. Outside of the old single CPU to multi-CPU "competition", I see none with respect to these two architectures. They are complementary in nature versus some kind of "replacement" due to limits.

Each CPU in a system has a socket in the board. This grants "off-chip" IO paths of a limited nature irrespective of the number of cores - 1 socket has a path to the rest of the system. So if operations require more off-chip access, multiple CPU's, each with their own bus, will outperform a single CPU with multiple cores. If, on the other hand, you have more "on-chip" processing/communications required, avoiding the CPU's communicate across the bus speeds up that communication plus "on-chip" functions will tend to be faster.

So it's comparing "on-chip" vs "off-chip" and a shuffle of where traffic jams can/will occur. With multiple-cores, they will hit a limit at the shared bus as the cores each require different "off-chip" resources so, at some point, how many cores can be stacked on a single slot/bus will be hit. Diminishing returns style. When? Like I said, it's not my main field and even if it were, I doubt it can be predicted beyond generalization versus exacting -- especially in the generic "computer" market that spans scientific through arts around to 'fun'.

For those looking for a higher performance single CPU slot solution, the multi-core systems tend to be far more cost effective than going with multi-CPU systems and this is how they are positioned in the market across platforms -- multiple-cores > 1 core. As such, this technology is flat out replacing single-cores across most systems that use them but not so with systems that use multiple CPU's -- they are moving (or have moved) to adopt this enhancement as part of their existing architecture.

Last; the NoC comment is also not needed in this area. That's a distraction that really adds nothing to defining multi-core processors in this "introduction" area. SoC if you like but NoC is more a separate "sub-system" commentary than dealing with a CPU's architecture. (sorry "network on a chip" = NoC)

--Eleazaros (talk) 05:36, 13 October 2010 (UTC)

Stanford Video on Programming Many-core computers

There is a new Stanford video on programming many-core computers at How to Program the Many Cores for Inconsistency Robustness with slides available at [1]. It argues for using the Actor model together with "Organizational Programming"24.180.11.235 (talk) 04:08, 19 January 2011 (UTC)