Which is faster - i7 2.5GHz or i5 3.1GHz?

Discussion in 'Buying Tips and Advice' started by Stormz, Jul 11, 2017.

  1. Stormz, Jul 11, 2017
    Last edited: Jul 11, 2017

    Stormz macrumors member

    Stormz

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    Aug 21, 2007
    #1
    I'm looking at buying a 13" MBP. Just deciding between touchbar vs non-TB, and comparing specs, but clockspeed is confusing me.

    All other things being equal, which is likely to be faster?

    Intel Core i7 - 2.5 GHz (Non-TB)
    Intel Core i5 - 3.1 GHz (TB)

    Both will be 16Gb RAM and 512Gb SSD.

    Thanks.

    [EDIT: I'll be using my Mac for Photoshop and coding. No audio or video production. Maybe watching some Netflix. Also just noticed the graphics cards differ - the i5 uses Intel Iris Plus Graphics 650, the i7 uses a 640. Not sure whether that makes much of a difference...]
     
  2. Hirakata macrumors 6502

    Hirakata

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  3. bbrks macrumors 65816

    bbrks

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    #3
    And that 2,3 % difference in speed would be important, because.......
     
  4. Stormz thread starter macrumors member

    Stormz

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    #4
    Thanks Hirakata. Can I infer from your answer that, for my needs, the i7 is actually faster than the i5 even when the i5 is a higher clock speed than the i7 as it is in the example above?
    --- Post Merged, Jul 11, 2017 ---
    Your point being, I shouldn't notice much difference for how I'll be using it - is that right?
     
  5. gnasher729 macrumors P6

    gnasher729

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    #5
    There's something about clock speed you have to know...

    A processor doesn't have just one clock speed. The clock speed is limited by the heat that the processor produces. 4 cores produce more heat than one. So a processor can run at the highest clock speed with only one core running, a bit lower clock speed with two cores used, and even lower clock speed with four cores used.

    Intel (and Apple) show the speed that the processor can run at, 24 hours a day, with all cores used. But the i5 has only two cores, the i7 has four. So you are comparing different things. If the i7 uses just two cores, it runs at the same clock speed as the i5, but it runs a little bit faster because the i7 is more efficient. But then the i7 can use four cores, and when it uses them, it runs circles around the i5.
     
  6. kschendel macrumors 6502a

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    #6
    The i7 boosts higher than the i5 (4.0 vs 3.5 Ghz), and as noted has hyperthreading enabled meaning effectively 4 cores instead of 2. (That's not strictly true, which is why both are listed as dual core, but the i7 can run two threads per core and the i5 only one.)

    Without seeing actual benchmarks, I suspect that the i7 can outrun the i5 for short bursts, but will throttle back harder, sooner. If you are running multiple concurrently active programs, or something that can multi-thread, the i7 will have an edge.

    Given what you're talking about doing with the computer, I'd consider them basically equal and make the decision on other grounds such as memory, SSD capacity, cost, etc. (I don't know how much difference there is between the graphics. A very quick google search seems to indicate 10-15% in favor of the 650.)
     
  7. Stormz thread starter macrumors member

    Stormz

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    #8
    That's really helpful information that you've both posted. Thanks very much.
     
  8. dollystereo macrumors 6502a

    dollystereo

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    #9
    This is true for desktop versions. The 13" inch macbook pro has dual core i5 and i7, and both are hyper threaded. So no, the i7 does not run circles around the i5.
     

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  9. kschendel macrumors 6502a

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    #10
    Those i5's are dual core, so you are correct about the hyperthreading. My mistake. That makes the two even more similar. The i7 has a higher max boost clock, the i5 has a higher base clock and slightly better integrated graphics. Flip a coin.
     
  10. kohlson macrumors 6502a

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    #11
    I don't think you'll see much of a performance difference in coding/compiling. The integrated GPUs may deliver a performance difference, both generally, and in PS. Any way you can take a stick with code and images to an Apple Store and try them out?
     
  11. TechZeke, Jul 12, 2017
    Last edited: Jul 13, 2017

    TechZeke macrumors 68020

    TechZeke

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    #12
    EDIT: Actually, you're mixing things up. I assume we are talking the i5s and i7s in 13" models, not the quad i7s in the 15" model.

    Both processors are hyperthreaded dual core CPUs. The TB model has a higher 28W TDP, but it won't make much of difference unless you are constantly maxing out the CPU. In all there'd be little difference.

    I'd also tell the OP to skip the processor upgrade, even if he goes with the non-TB model. Despite the nomenclature, the i7 upgrades on the 13" models are nothing more than faster clocked i5s with some extra cache. again, all are dual core with hyperthreading.
     
  12. ZapNZs macrumors 68020

    ZapNZs

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    #13
    I do not think you would see much of a difference even between the base nTB's i5 and the TB's flagship i7. The 640 v. 650 appears to be a very small difference, and for your usage you probably would not notice any difference between the two.

    Consequently, unless you want the touchbar (and I imaging you likely favor the physical function keys for coding), if it were me I would personally favor the base model nTB's 2.3 GHz i5, and put the money saved on skipping the upgraded CPU/TB towards upping the RAM to 16 GB, increasing the SSD size, or accessories for use such as an external display, Thunderbolt 3 dock, and/or external SSD.
     
  13. Stormz thread starter macrumors member

    Stormz

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    #14
    I'll definitely max out the RAM and get a 512 SSD, but even so, would the base model nTB 2.3GHz i5 be adequate for Photoshop do you think? While most of it is for web use so small, very occasionally I'll be working on print files that are 600 MB or more.
     
  14. kschendel macrumors 6502a

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    #15
    I would have to think so. The CPU difference between the lowest-spec nTB processor and the highest spec TB processor is on the order of 50% and that's pure CPU; for real work it's going to be less than that. Unless you are insisting on the fastest possible response, and are willing to pay the $600 difference, the "slow" machine will be at least adequate and most likely entirely acceptable. The SSD and memory you are spec'ing are just as important to overall response time.

    I'm inclined to agree with ZapNZs that the base nTB with 16 Gb RAM and 512 Gb SSD is likely to be the best value for you.

    (If you DO decide to throw money around, I'd say go all the way to the top spec TB; paying $300 for a couple hundred MHz bump for the nTB model makes very little sense to me.)
     
  15. green86 macrumors 6502

    green86

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    #16
    I'm sorry, the information your getting here is bad. The i5 is faster. Intel has been heavily criticized this year for their confusing naming conventions. The i7 is an inferior chip. They have the same amount of cache, the same number of cores, and they have both have hyper threading. Get the TB MacBook Pro. The turbo boost speed is the only advantage, but only kicks in when the chip is cool enough. So with the i5 your guaranteed 600 Mhz faster all the time, (3.1 Ghz vs 2.5 Ghz) vs 500 Mhz some of the time (3.5 Ghz vs 4 Ghz).
     
  16. kschendel macrumors 6502a

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    #17
    Except when it's slower. As stated in previous posts, the i5 is faster unboosted, the i7 is faster boosted. I don't think that's particularly ambiguous. If you need maximum CPU speed you want the TB model with the top i7 chip, but I don't see that the OP needs to pay the $600 difference for doing photoshop and running compiles.
     
  17. DarkSel macrumors regular

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    Dec 22, 2012
    #18
    The i5 has a higher TDP and will run at boost clocks for much longer than the i7 with the lower TDP. Hence, the i5 will be faster.
     
  18. kschendel macrumors 6502a

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    Dec 9, 2014
    #19
    *sigh*. Except when it's slower.

    Come on, people, let's convey facts properly. The i5 will not be faster unconditionally, so don't say it that way. The i5 will be faster unboosted and will likely maintain a boost longer. The i7 will boost to a higher clock rate, even if it doesn't hold it as long; and if that fits a particular use-case, the i7 will be faster for that use-case.
     
  19. green86 macrumors 6502

    green86

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    #20
    Fine, you want to be specific? The i5 is faster most of the time. The i5 is faster, more often. Sometimes the best route to go is to admit your wrong.
     
  20. kschendel macrumors 6502a

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    Dec 9, 2014
    #21
    Yes, that's what I was looking for.

    Indeed, and it was very good of you.
     
  21. Stormz thread starter macrumors member

    Stormz

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    #22
    By the sound of it, you're all mostly in agreement, just differing on emphasis and semantics (like most internet debates in fact!). Thanks for all your input. I'm thinking of taking your advice ZapNZs and kschendel and going for either the nTB i5 2.3GHz, or if I want more power, then (in for a penny, in for a pound) leapfrog the nTB i7 in favour of the TB i5 3.1GHz. Still, it's good to know the base one is likely to be adequate if I go down that route. As you say, RAM and SSD will be bigger considerations.
     
  22. ZapNZs macrumors 68020

    ZapNZs

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    #23
    Yes, in my opinion.

    I do not think you will see much of a difference between the different CPUs for what you do, and, so if it were me I could not justify the higher price of the upgrade nTB i7 or the TB's i5/i7 (unless of course you want the touch bar.)

    If it were me, I would take the $300 - $600 savings and either save it or put it towards an external SSD or HDD, a Thunderbolt 3 charging dock, a NAS setup, and/or a nice external display/speakers for watching videos/movies.
     
  23. Stormz thread starter macrumors member

    Stormz

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    #24
    Mmm, when you put it like that...
     
  24. Ridiculous Mime macrumors newbie

    Ridiculous Mime

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    Jul 30, 2017
    #25
    Similar question:

    Choosing between Macbook Pro 13" models, based on my needs.

    It will be used for electronic music production/mix editing (along with real estate work)

    Budget is 1800 or so, but preferably closer to 1500. Where do I place my focus? Based on what I've read, there's not a whole lot of difference between the 2.3 i5 and 2.5 i7, although my friend advised me to get an i7 if possible. I imagine I'll be using ableton Live, which asks for 4gb of ram minimum.

    If it comes to music production, would it be more advantageous to increase the ram from 8gb to 16gb for $180, or upgrade the chip from 2.3 i5 to 2.5 i7 for $270?

    The third option is to go with the Touch Bar model, which adds $450 to the base price of $1250, but adds the Touch Bar, takes the storage from 128gb to 256gb, and upgrades the processor from a 2.3 i5 to a 3.1 i5. But the ram upgrade is still another $180 (I'm not too concerned about storage, because music will be stored externally)

    Is any of this even necessary? I'm tempted to abide by my friend's advice to get an i7, but it doesn't seem to do much for me for the $270, and I'm not sure what to prioritize.
     

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