Difference between new i5 and i7 CPU?

Discussion in 'iMac' started by Blind4Seven, Jul 28, 2010.

  1. Blind4Seven macrumors newbie

    Joined:
    Jul 28, 2010
    #1
    Hi,

    I need a new imac 27" and can't decide between i5 and i7.

    Is it worth the upgrade?

    I'm using Logic, Photoshop, Flash Builder, XCode, movie stuff very often.

    Thanks.
     
  2. Hellhammer Moderator

    Hellhammer

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    #2
    Do you do video editing? i7 has Hyper-Threading which can boost by up to 30%. IMO i7 is worth it but the apps you listed don't benefit much from it
     
  3. TMRaven macrumors 68020

    TMRaven

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    Nov 5, 2009
    #3
    The stuff you have mentioned will benefit more from added ram and SSD.
     
  4. Blind4Seven thread starter macrumors newbie

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    Jul 28, 2010
    #4
    I do video editing as well. What about gaming?

    Doesn't i7 support DDR3 ram? Or does i5 also?


    Thanks.
     
  5. MythicFrost macrumors 68040

    MythicFrost

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    Australia
    #5
    An extra $200 to future proof your computer as well as provide extra performance to anything that needs it that you already do is well worth it in my opinion.
     
  6. Hellhammer Moderator

    Hellhammer

    Staff Member

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    #6
    There ain't huge difference in gaming.

    All iMacs since March 2009 use DDR3.

    I would get at least 8GB of RAM from aftermarket so if you can afford i7 + 8GB (around 100$ from 3rd party), then it's the way to go. If you want to save 200$, then get the i5 with 8GB
     
  7. JoelMarcey macrumors 6502

    JoelMarcey

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    Location:
    Northern California
    #7
    Yes, i5 supports DDR3.

    Hardcore video editing/encoding, hardcore gaming could take advantage of the i7 HT capability. I basically use iMovie for general video editing, rip a couple of movies every now and then, so the i5 was just fine for my purposes.
     
  8. tollerite macrumors newbie

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    Jul 28, 2010
    #8
    Would the i7 not produce a power-boost for Logic wrt i5 ?

    Incidentally, slightly OT, can someone tell me what is new about the new iMac i7 - same processor as before yeh? Does is have a better graphics card?
    .... now the new one is out - I can't find the specs for the old one ...
     
  9. Frobozz macrumors 65816

    Frobozz

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    Location:
    South Orange, NJ
    #9
    Get the Core i7. The math is very compelling for the $200 you will spend. The Core i7 has a 4.6% faster clock speed and it has TWICE the logical cores.

    A faster dual core CPU (the Core i5) will usually beat the 4-core (Core i7) in gaming performance because you can purchase it at a faster core clock speed. However, Apple is not doing that here because it's confusing to consumers. You can buy a 3.6 GHz Core i5 on the open market– it just isn't an option here.

    Basically it's an apples-to-apples comparison at the same clock speed, until you come to hyper-threading. The Core i5 and i7 have the same Turbo Boost mode features, memory bandwidth, and so forth. The Core i5 just doesn't have hyper-threading. If you were doing 3D modeling, CAD, or video editing, you'll see a significant boost from a Core i7's hyper-threading, even if you had a faster clocked Core i5, because it would be like having two Core i5's to that software!

    Now, for compiling code or Photoshop, you want an SSD and a lot of RAM. However, the SSD can be extremely expensive. But believe me– compiling code on an SSD will spoil you. My buddy at work has his desktop set up with the 80GB Intel X25M as his boot / compile drive. It's a VAST, VAST improvement over a spindle. If your time is money, you can justify that.

    Hope this helps.
     
  10. dexthageek macrumors 6502

    Joined:
    Dec 7, 2007
    #10
    Run a quick search on the forum. There have been a number of topics posts that discuss this very question.

    To quickly answer your question.

    iMac i7 (2010) offers minor bumps in CPU and GPU.

    CPU
    (2009) i7 2.8Ghz
    (2010) i7 2.93Ghz

    GPU
    (2009) ATI HD Radeon 4850 512MB
    (2010) ATI HD Radeon 5750 1GB
     
  11. frega macrumors member

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    Jul 28, 2010
    #11
    There's actually 3 different types of CPUs for the 27", all 3 can be BTO'd with the Radeon 5750 (5850m).

    i5-680 Dual Core
    3.60GHz
    3.86Ghz Turbo Boosted
    HT

    i5-760 Quad Core
    2.80Ghz
    3.33Ghz Turbo Boosted
    NO HT

    i7-875k Quad Core
    2.93Ghz
    3.60Ghz Turbo Boosted
    HT

    After reading multiple threads, I still can't discern which is better for gaming? Some say "more physical cores is better". But some say "Hyperthreading hurts gaming". Then there's the different architecture for the i5s, Dual Core 32nm Westmere("Clarkdale") vs the Quad 45nm Nehalem("Lynnfield").

    If someone can put it all into perspective...
     
  12. Blind4Seven thread starter macrumors newbie

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    Jul 28, 2010
    #12
    Thanks a lot for your replies.

    I really appreciate your comments.

    Think I will wait 2 more months to get the i7 and maybe more ram or even the ssd.
     
  13. Hellhammer Moderator

    Hellhammer

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    Finland
    #13
    It's i7-870, not 875K ;)

    The issue is that it depends on the game. In some games, the Clarkdale is better due the clock speed but in some games the Lynnfield is better due the extra cores. In benches I've seen the quad is better

    http://www.anandtech.com/show/2901/12
    http://www.anandtech.com/show/2901/13
     
  14. tollerite macrumors newbie

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    Jul 28, 2010
    #14
    Thanks for this - I was really confused with the different processors until I realized there are 2 different i5s - a dual core and a quad core - this doesn't seem to be at all explicit in the apple store (or maybe I'm just blind).
     
  15. dexthageek macrumors 6502

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    Dec 7, 2007
    #15
    Don't forget about the i3 available in the base 27''

    3.2GHz Intel Core i3
     
  16. zappster macrumors newbie

    zappster

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    Mar 23, 2010
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    Niverville, MB, Canada
    #16
    Based on these charts, with the exception of a couple of tests, there is little difference between an i3 and i5. I may be off base here, but based on this, I think the best value is either the base i3 systems, or go right to the Quad i5 (unless you need or can afford the extra cost to go i7).
     
  17. Dreadnought macrumors 68020

    Dreadnought

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    Jul 22, 2002
    Location:
    Almere, The Netherlands
    #17
    Totally agree here, it seems that the quad i5 @2.8 Ghz totally outperforms the dual i5 @3.6Ghz, as I compare it with these tests. I had a doubt which processor to choose, the dual i5 or the i7. I'll think I'll pick up an iMac i7 to replace my old dual PM G5 1.8. Thanks for the links to the tests! If someone has tests or benchmarks of the procs used in the new iMacs, please post the link!!
     
  18. Irishman macrumors 68030

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    Nov 2, 2006
  19. Rudy69 macrumors 6502a

    Rudy69

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    Mar 30, 2009
    #19
    I was planning to buy the i7 (sold my 27" Core 2 Duo to buy an i7 :p) but the local Apple Stores aren't stocking them (well at least not in the next few weeks).

    So now my dilemma is waiting for the i7 or buying the Quad i5....

    The main thing I was looking forward to was to be able to compile 8 files at once in Xcode (the i5 quad would only do 4...). I don't game or anything else, I mostly browse the net and code (but lately the compiling time is getting a bit out of hand....and no I'm not getting an SSD....too pricey)

    So what do you guys think? i5 or i7?
     
  20. napos macrumors newbie

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    Jan 12, 2007
    #20
    I want someone to tell me between the i3 (dual), i5 (dual), i5 (quad) and i7 (quad) in terms of handbrake performance. That's the the most strenous application I will put an iMac through.

    What about i3 dual vs i5 dual in handbrake? (if I stay with 21.5")
     
  21. Hellhammer Moderator

    Hellhammer

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    #21
    i7 will run circles around those others. However, if you don't do much HandBraking, then stock i3 is fine but if you're going to do it a lot and frequently, then i7 is worth it.
     
  22. zachUK macrumors newbie

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    Jul 25, 2002
    Location:
    London
    #22
    Has anyone actually checked which chip it is? Is there any substantive difference between an 870 and 875K?
     
  23. Hellhammer Moderator

    Hellhammer

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    Finland
    #23
    875K has unlocked multiplier and costs 48$ more. That's all. Seeing that you cannot overclock under OS X, it would be totally useless for Apple to include 875K instead of 870, especially because Apple loves the every extra dollar they can get.
     
  24. southerndoc macrumors 65816

    southerndoc

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    May 15, 2006
    Location:
    USA
    #24
    If I'm running multiple programs (Safari, Mail, iChat, Photoshop, resource-heavy iTunes, etc.), will each program run on a separate core if available?

    I've found my current C2D iMac has lag periods sometimes when I'm listening to music through iTunes.
     
  25. JohnRN macrumors member

    JohnRN

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    Mar 31, 2010
    Location:
    Atlanta, GA
    #25
    I don't believe it works quite like that. Someone please correct me if I'm wrong but programs are designed to utilize so many cores. So if you have three programs all running that are designed to utilize 4 cores, the work load will be spread out among those four cores with each program taking a little bit of each of the four. I believe the same goes for ones that utilize two cores, etc. If you have a four core machine and the program can only use two, two will be used, and the other two ignored. I believe then that controller within the mac or OSX is what then decides what cores to send the programs too. But that is all beyond my understanding.
     

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