MBA vs MBP..... processors

Discussion in 'Buying Tips and Advice' started by reese2147, Feb 6, 2015.

  1. reese2147 macrumors regular

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    #1
    Good Evening,

    I've had an iMac for the past 5 years. I recently sold it in order to purchase either a MBA or MBP to have a more portable computing option.

    I'm not a very heavy user.... primary email, web browsing and Adobe Photoshop for a little graphics work I do. "Responsiveness" is important to me, I want to be able to turn on the machine and fire up apps quickly. After looking at the options between a MBA and MBP, I have one basic question about processors... please forgive my complete lack of technical knowledge around processors....

    The MBA I am pondering has a 1.7GHz Dual-Core Intel Core i7, Turbo Boost up to 3.3GHz. The MBP I am looking at has a 2.8GHz Dual-core Intel Core i5, Turbo Boost up to 3.3GHz. Both of these processors "turbo boost" to 3.3 GHz, but have different "base" GHz.

    I have no idea what "turbo boost" means here..... In non-technical speak... is there any true difference between these two processors and is there any noticeable difference in their performance within their respective machines?

    Thank you for your input.
     
  2. Traverse macrumors 603

    Traverse

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    #2
    An advantage to i7 processors is the support of hyper-threading. This means that a dual-core i5 chip will register as two cores to the system whereas a dual-core i7 will register as four cores (two physical and two virtual). This could help with multi-core performance for apps that support it.

    Example: my quad-core macbook pro register 8 cores and divides the processor intensive workload among those cores as needed.
     
  3. dyt1983, Feb 6, 2015
    Last edited: Jun 1, 2015

    dyt1983 macrumors 65816

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    #3
    edit: To remove personally identifying info not relevant to the conversation.
     
  4. Traverse macrumors 603

    Traverse

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    What's interesting is the configuration page for the 13" rMBP mentions hyper threading, but the page for the MBA doesn't mention it for i5 or i7.
     
  5. Anonymous Freak macrumors 601

    Anonymous Freak

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    #5
    As dyt1983 mentioned, all dual-core i5 CPUs have hyperthreading. More specifically, Intel uses "i3 = two total threads, i5 = four total threads, i7 = four or more total threads." So all i3s are dual-core, no hyperthreading. All i5s are either dual core with hyperthreading, or quad-core without it. i7s can be either dual core with hyperthreading, or quad-core with or without hyperthreading.

    As for "turbo" - that means that when the system is using only one CPU core heavily, and it has power and thermal headroom (aka: it's not overheating,) it will run at up to that speed. Smaller/lighter systems have lower total power overheads, and generally less effective cooling systems, so they are more likely to reach that limit more quickly.

    For a single-thread workload, that is short in duration (a few seconds to a minute,) the two systems would be very similar in performance. For multi-threaded workloads, the lower-base-speed CPU will end up slower, because the multi-core turbo speed is lower on that CPU than on the higher-base-speed CPU. For heavy CPU workloads that last longer (more than a minute,) you're more likely to run in to heating issues, thereby slowing down sooner.

    Likewise, both systems have integrated graphics, that share the same power/heat limit. So 3D operations will be slower due to the power/heat limit, as well. And 3D operations going at the same time as CPU operations will severely limit the amount of turbo available for the CPU. (The lower-base-speed CPU is more likely to have the 3D portion using up more of the total power available, thereby making it less likely that the CPU can turbo all the way up.)


    tl;dr: The Air will be very similar in performance for most day-to-day operations, but in process-intensive, or 3D-intensive, it will slow down noticeably compared to the Pro after a minute or so as it heats up.
     
  6. dyt1983, Feb 6, 2015
    Last edited: Jun 1, 2015

    dyt1983 macrumors 65816

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    #6
    edit: To remove personally identifying info not relevant to the conversation.
     
  7. reese2147 thread starter macrumors regular

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    #7
    Thanks for this explanation. If I am understanding all of this right, the processor really doesn't have much to do with the responsiveness of the machine, just how it handles apps once they are up and running?
     
  8. Santabean2000 macrumors 68000

    Santabean2000

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    #8
    Yup.

    look at the difference in screen quality too. The MBP is a clear winner in my mind.
     
  9. dyt1983, Feb 7, 2015
    Last edited: Jun 1, 2015

    dyt1983 macrumors 65816

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    #9
    edit: To remove personally identifying info not relevant to the conversation.
     
  10. reese2147 thread starter macrumors regular

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    #10
    Ha ha, you are correct. Portability really isn't an issue for me. To be perfectly honest, I was considering the MBA strictly due to it being a tad less expensive than the MBP.

    Display "quality" really isn't a big deal to me. I am typing this message on a 2007 MBP and find the display quality just fine for me. My largest concern is how the systems will perform when I have Safari, Mail and Photoshop open at the same time :)
     
  11. Santabean2000 macrumors 68000

    Santabean2000

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    In that case, just choose the cheapest; they're all perfectly capable of doing what you're describing.

    [The reason I mentioned the screen is that it's the thing that will make a difference to your user experience EVERY time you use the machine. The iPhone 3G screen was 'good enough' until I started using the iPhone 4, my iPad 2 was 'good enough' until I started using an iPad Air. I would never like to go back; I know you'd feel the same once you move to a retina MacBook.]
     
  12. thekev macrumors 604

    thekev

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    #12
    I don't think you have much to worry about. PS only becomes a resource hog when you stack things up, such as high resolution, 16 or higher bits per channel, and many layers + thumbnails on and a number of history states retained. Your work doesn't sound like that.
     
  13. Anonymous Freak macrumors 601

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    #13
    Sorry, yeah, I was referring to mobile, and I should have specified that. On desktop, i3 and higher all have four or more threads. (I was working for Intel when the CPU you linked to came out - there was much confusion even internally over what differentiated each model.)
     
  14. GreatDrok macrumors 6502a

    GreatDrok

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    #14
    I've had both a 13" MacBook Air with the i5 (yes, it showed as quad due to hyper threading) and now have a 13" rMBP i5. Performance is barely different, but I switched because I wanted more memory than the top Air could support (8GB on Air, 16GB for the Pro)

    The screen on the Pro is nice but you actually end up with less room compared with the Air because the Pro acts like a 1280x800 screen and the Air has an actual 1440x900 but you can push the Pro to do 1440x900 or 1680x1050 through the display settings using the 'scaled' options and they don't look fuzzy like you might expect, still retina and very clear. I like the Pro for that but it is a little heavier than the Air and the battery life isn't quite as good (about 8-9 hours for the Pro versus 12 or so for the Air)

    Other than that, the keyboard and trackpad are identical, they both have USB3 so fast connectivity is there. The Pro has two display port/thunderbolt sockets versus one on the Air and it also has an HDMI socket which I find very handy. On the other hand, the Pro I got is quite a bit more expensive than the Air was largely because I bumped the RAM and SSD sizes. I wouldn't worry much about the speed of the CPU as long as you have enough storage and RAM because while you can upgrade the storage, you'll be stuck with whatever RAM you have and I only had 4GB on my Air and for all the work I do that wasn't enough. 8 might have worked, but I use virtual machines a lot so 16GB was a much better choice. In your case, the 8GB i5 13" Air with 256GB SSD would probably work perfectly.
     
  15. reese2147 thread starter macrumors regular

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    Thank you for this write up. I do think I am going to end up going with the MBA. Wish me luck!i
     
  16. GreatDrok macrumors 6502a

    GreatDrok

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    #16
    Good luck! ;)
     

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