What does more cores mean?

Discussion in 'Mac Pro' started by M-apple-T, May 14, 2008.

  1. M-apple-T macrumors member

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    Apr 14, 2008
    #1
    I hear people saying stuff like " to bad that 8 cores wont be used" Or " 8 cores can actually be slower and 2 cores"
    How is that?
    Wouldn't a 8 core 2.8ghz be faster than the 4 core 2.8ghz in the mac pro?
    What would the 8 core be good for? Or doing what puts those 8 cores to use?
    And finally is the 8 cores worth getting?
    I don't know to much about this stuff.
    thanks
     
  2. darthraige macrumors 68000

    darthraige

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    #3
    8-Cores was definitely worth getting. For me anyway. I use Compressor a lot and to encode an hours worth of video with 1 core takes about real time. Turn all 8 bad boys on and it takes about 10 minutes.
     
  3. Infrared macrumors 68000

    Infrared

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    #4
    22.4GHz of Mac Power!

    ( sorta ;) )
     
  4. Virgil-TB2 macrumors 65816

    Virgil-TB2

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    #5
    I think the bottom line in layman's terms is that everyone thinks that having more cores will give you a faster machine and a faster computing experience when it won't at all actually. Almost all software will just take advantage of the one (first) core and run at the same speed it always has.

    The *advantage* to multiple cores is that you can run multiple things at the same time without slowing down. So whereas you used to have to pretty much leave the computer alone when something really intensive was going on in an application, with a multi-core machine you can just start up something else with no fear of crashing or slowdown.
     
  5. FF_productions macrumors 68030

    FF_productions

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    #6
    There are certain apps that won't take advantage of multi-core processing. Cores are more efficient than more physical processors these days, so that's why Core is the big thing.


    An 8-Core Mac Pro can be as fast an iMac in some instances, because the app has not been totally optimized. Also, other factors go into making a multi-core faster such as faster hard disks (always a bottleneck) and more ram.
     
  6. nick9191 macrumors 68040

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    #7
    If you have applications that can utilise multi cores (and multi cpu's in the mac pro's case) then it is. However many games for example still can only use 2 cores, so a 3ghz core 2 duo would beat a 2 x 2.8ghz quad core xeon mac pro (that and the xeon is not for gaming but you get what I meant).

    Personally I would buy the 8 core just because its not much more than the 4 core mac pro, and to be more future proof when apps do go more multi core, and for bragging rights of course.
     
  7. macz1 macrumors 6502

    macz1

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    Oct 28, 2007
    #8
    Fortunately (for Mac pro owners) more and more software developers try to optimize their products for multiple cores. Dual core is getting standard and everybody can see that in the future the number of cores will increase faster than their clock frquency.
    More cores are future proof in my opinion
     
  8. Roy macrumors 6502

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    Jul 6, 2006
    #9

    21.75 percent more.
     
  9. nick9191 macrumors 68040

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    #10
    Okay for me it would cost £294 more to get the 8 core over the 4 core model, whether its just good marketing etc. but for double the cores, and to know that when multi-core apps are more in number, that this thing will really push its weight over the 4 core, it feels cheap.
     
  10. JonR356 macrumors member

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    #11
    That's not really the bottom line, as many applications (especially professional applications which are CPU intensive) will use multiple cores effectively.
     
  11. Roy macrumors 6502

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    Jul 6, 2006
    #12
    I see a lot of people make the same statement, but they never provide names. Not saying it isn't so, but names of the applications would definitely be better than "many applications". If you could provide the names of the applications and the maximum number of cores each uses effectively, then we can determine what the word "many" means.
     
  12. GoCubsGo macrumors Nehalem

    GoCubsGo

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    #13
    More cores makes up for things I otherwise lack in. :rolleyes:
     
  13. Virtuoso macrumors regular

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    Feb 21, 2008
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    Seattle
    #14
    Sadly this applies to the vast majority of applications, the main exceptions being high end 3D modelling and animation apps, where the rendering has been properly optimised for multi-threaded processing.

    Fire up Activity Monitor when you're working on something processor intensive and 9 times out of 10 you'll be disappointed to see that only 1 or 2 cores are actually being used. A time consuming lens blur on a massive image in Photoshop, for example, barely uses 15% of my CPU. This is because the application hasn't been written to use all 8 cores effectively - a legacy from the days when most people only had one single core processor.

    If you're doing multiple processor intensive tasks in several applications at once, it will speed things up (provided you have a ton of memory), but how many of us actually work that way?
     
  14. D4F Guest

    D4F

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    #15
    Cinema 4D allows you to use full 8 cores for example.
    And that's about it from what I use :D

    Future proof or not I still went with quad core. For me 8 cores is a overkill in 95% of time. I really don't care if I wait 10 or about 16-17 minutes (as you know core usage multiplier is not 1 to 1 and it decreases with every additional core) especially that I render a scene (i'm talking full settings with raytracing and etc) once in every few days. My Pro it's due to arrive tomorrow and I'm not complaining with my iMac so I know that 4 cores will be perfect and I still was left with $530 (with tax) and bought the 8800 GT and a better 500GB HD.

    It all comes down what you need. I'm more than sure that next 2 years will not change much in software department. Heck most of the apps are still 32bit and let alone coded to use 8 cores. You can have 32GB RAM in your mac yet there is not a SINGLE application that will use more than 4GB at a time. There's a lot to be improved and cores is just one thing.

    You're safe even with a C2D iMac for next 2 years. That's my $.02
     
  15. mchalebk macrumors 6502a

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    Feb 4, 2008
    #16
    I believe the iLife suite will take advantage of multiple cores. I've only got a dual processor machine, but iDVD maxes out both processors. If I'm not mistaken, all Apple apps can take advantage of multiple cores. Also, it's my understanding that Handbrake can use all 8 cores.
     
  16. JeffDM macrumors 6502a

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    #17
    Specifically, Apple-branded non-pro software doesn't use any more than two cores per app. Quicktime compression almost never takes more than two cores per file, but it will process more than one file at a time. EyeTV's conversion will only take two cores. I've had iDVD take half a core's worth because its audio compressor is poorly optimized.
     
  17. portent macrumors 6502a

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    #18
    Even if your app of choice only uses two cores, you can let it churn away unhindered, at full speed, while simultaneously continuing to use your other 2-6 cores to do other tasks. Something not possible on a 2-core machine without taking a hit.
     
  18. gkarris macrumors 604

    gkarris

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  19. orpheus1120 macrumors 65816

    orpheus1120

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    #20
    In short, you can run multiple apps that utilise less that 8 cores simultaneously or a couple of apps that use full 8 cores without problem. Its that simple.

    8-cores machines are not specifically designed solely for 8-cores apps these days. There are just too few apps of that calibre right now. Their primary advantage currently is to allow more apps that use less cores to be ran at the same time without performance hit. It's like having a big hard drive where you are able to store more number of small-sized data. You don't normally just store a single 500gb data on a 500gb hard drive do you?
     
  20. gkarris macrumors 604

    gkarris

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    #21
    ooooh, ooooh, ooooh (raises hand....)

    For Windows (or OS X?) if a program is not multiprocessor aware (only sees one core), is the OS smart enough to run the programs on their own core?
     
  21. JeffDM macrumors 6502a

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    Sep 16, 2006
    #22

    It's not a "these days" thing, multi-CPU systems didn't ever need to run multi-CPU software to operate.

    Drives and CPU as resources are not comparable in my opinion. Drives are a bit more of a fixed resource, most data isn't deleted so quickly, whereas an app that doesn't need CPU anymore vacates itself.

    I have a very hard time maxing out four cores with a lot of little apps. Most software really doesn't take much CPU. The stuff that does use a lot needs to be better optimized. I really don't care to run a lot of apps, I want fewer apps to run faster than have to manage a lot of apps. I don't think making the user manage a lot of little apps is a productive use of a person's time.
     
  22. orpheus1120 macrumors 65816

    orpheus1120

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    #23
    True majority of the users are not currently using multiple apps at the same time, which is why the mp may not be suitable for them. These users have better luck with the 3.06 imac or the quad core mb. But I have never doubt the presence of users with multiple apps utilisation. People in weather forecasting industry, media (publishing, news, graphic rendering) often use a couple of cpu-intensive apps and a few less cpu-intensive apps together. With 8 core the process is smoother and more future proof. For industries where efficiency and time is an essence, machines like the mb is an asset. If companies like walt disney are using the imac for their rendering, I doubt I can watch narnia today.

    Remember there are actually people who needs the 8 cores or else Apple wont offer them. If you dont, perhaps the mac pro is just not for you yet.
     
  23. martinlk macrumors member

    martinlk

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    Aalborg, Denmark
    #24
    Yes. The OS's scheduler will see to it that processes are distributed among the available cores. For instance, if you have two single-threaded apps (not "multi-core aware") running that are both cpu intensive, the OS will assign both apps to each their core and not not both apps on the same core. In other words, the scheduler will always try to distribute threads in order to maximize throughput.
     
  24. Infrared macrumors 68000

    Infrared

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    Mar 28, 2007
    #25
    Don't forget compilation!

    If you want to build a largish project, having
    lots of cores can make a dramatic difference.
     

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