2011 MacBook Pro CPU/GPU Addendum

Discussion in 'MacBook Pro' started by Evil Spoonman, Feb 25, 2011.

  1. Evil Spoonman, Feb 25, 2011
    Last edited: Feb 26, 2011

    Evil Spoonman macrumors 6502

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    Jan 21, 2011
    Location:
    California
    #1
    With the way Sandy Bridge has centered around a single chip, obviously picking that chip has become more complex and more important. Now we have a GPU, a CPU, a memory controller, a power management system, and more bundled together. So what does this mean for selecting which MacBook Pro you get? The devil is in the details:

    Presuming I am correct about the chips (not verified). Note that the i5-2410M is an OEM SKU.

    MacBook Pro 13"

    Common
    - 2 Physical Cores, 4 Logical Cores
    - 12 EU Intel HD 3000 Graphics
    - 35W
    - Dual Channel 1333MHz memory
    - DMI 2.0
    - 384MB Shared Memory for IGP

    i5-2415M (base 13" - Exact Specs Unknown)
    - CPU Base Clock: 2.3GHz
    - CPU Turbo Clock (1C/2C): 2.9GHz/2.6GHz
    - Cache: 3MB
    - Graphics Standard Clock: 650MHz
    - Graphics Max Turbo Clock: 1,300MHz?

    i7-2620M (premium 13")
    - CPU Base Clock: 2.7GHz
    - CPU Turbo Clock (1C/2C): 3.4GHz/3.2GHz
    - Cache: 4MB
    - Graphics Standard Clock: 650MHz
    - Graphics Max Turbo Clock: 1,300MHz


    When selecting a 13" MacBook Pro, your choice of processor could also affect how fast your graphics are. The IGP onboard Sandy Bridge is tied in to the same memory controller, L3 cache/bus, power gating system, and whatnot as the CPU itself. It also shares the same thermal envelope. How much faster the GPU is on the higher end 13" depends on what you're doing. It will range between not at all to somewhat. The GPU will not be allowed to turbo all the way up if the CPU is active in a significant way. Games such as Starcraft 2 which tend to consume their fair share of CPU will probably not see any benefit at all.

    The CPU speed difference on the other hand is considerable, and consistent. 500MHz across two cores at all turbo bins. Sandy Bridge bins in 100MHz increments, not 133MHz like Nehalem.

    What's the best way to get the most out of your 13" GPU? Run your memory in matched pairs at 1333MHz so that the dual channel architecture can leverage maximum speed. Keep your CPU usage down when possible while doing graphics intensive things to allow the GPU's turbo to max out.



    This appears to also be the case for the 15" models as well. The 17" is unaffected, housing only the top-shelf chips anyways.

    MacBook Pro 15"

    Common:
    - 4 Physical Cores, 8 Logical Cores
    - 12 EU Intel HD 3000 Graphics
    - 45W
    - Dual Channel 1333MHz memory
    - DMI 2.0
    - 384MB Shared Memory for IGP

    i7-2635QM (base 15")
    - CPU Base Clock: 2.0GHz
    - CPU Turbo Clock (1C/2C/4C): 2.9GHz/2.8GHz/2.6GHz
    - Cache: 6MB
    - Graphics Standard Clock: 650MHz
    - Graphics Max Turbo Clock: 1,200MHz

    i7-2720QM (premium 15")
    - CPU Base Clock: 2.2GHz
    - CPU Turbo Clock (1C/2C/4C): 3.3GHz/3.2GHz/3.0GHz
    - Cache: 6MB
    - Graphics Standard Clock: 650MHz
    - Graphics Max Turbo Clock: 1,300MHz

    i7-2820QM (BTO 15")
    - CPU Base Clock: 2.3GHz
    - CPU Turbo Clock (1C/2C/4C): 3.4GHz/3.3GHz/3.1GHz
    - Cache: 8MB
    - Graphics Standard Clock: 650MHz
    - Graphics Max Turbo Clock: 1,300MHz


    In this light, the upgrade to the high end model 15" makes a lot more sense. You end up getting a lot more CPU clock when you take into account Turbo. It isn't just an extra 200MHz, it's an extra 400MHz even with all cores active. You get a small bump in the IGP maximum speed as well. Not to mention the vastly better dGPU and other goodies.

    The i7-2820QM BTO option looks less attractive. It is truly only 100MHz across the board, and a 2MB L3 cache increase.



    When comparing the premium 13" to the base 15", one cannot ignore the dGPU. Although the 6490M is not a great GPU, and short on video memory, it is still massively faster than the HD 3000 (especially the weak one in the base model 15"). Comparing purely on a processor level, the premium 13" CPU is faster in poorly threaded operations due to a somewhat higher clock (500MHz). When you begin to see heavily threaded tasks, the 15" will be quite a lot faster. Really it depends which applications you use frequently. Either way, the premium 15" CPU is roughly as good or better than the premium 13" for lightly threaded loads, and far superior for heavily threaded ones.



    Hope this helps some people decide. Cheers.
     
  2. Mackilroy macrumors 68040

    Mackilroy

    Joined:
    Jun 29, 2006
    #2
    Interesting information. I'll keep this in mind if/when I upgrade.
     
  3. c1phr macrumors 6502

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    Jan 8, 2011
    #3
    Pretty good info here, I believe this calls for a sticky! Good work Evil Spoonman
     
  4. doingitlive macrumors member

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    Jan 20, 2011
  5. Eddyisgreat macrumors 601

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    Oct 24, 2007
    #5
    Stick around for a few months and you'll realize that even the most helpful of information doesn't receive a sticky. That's the mod's decision, unfortunately.
     
  6. fortunecookie macrumors regular

    fortunecookie

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    Dec 3, 2010
  7. Evil Spoonman thread starter macrumors 6502

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    Jan 21, 2011
    Location:
    California
    #7
    As I said in the main post, The 17" is unaffected, housing only the top-shelf chips anyways.
     
  8. MUBiomed macrumors 6502

    MUBiomed

    Joined:
    Apr 24, 2010
    #8
    I was really wanting the 13" form factor and was considering the "premium" 13" for the i7 but decided on the new base 15". I think it was definitely the right decision and surprisingly enough I am actually liking the larger form factor. :D
     
  9. commander.data macrumors 65816

    Joined:
    Nov 10, 2006
    #9
    http://www.macrumors.com/2011/02/25/new-macbook-pro-benchmarks-show-massive-improvement/

    Apple is actually using the i7-2635QM for the 2.0GHz model, according to Geekbench, so the IGP speed difference is only 100MHz, which isn't that important given there is a dedicated GPU.

    The low-end 13.3" MacBook Pro is also reported to use a 2.3GHz i5-2415M which doesn't appear to be an official Intel part. It's probably a custom solution with increased IGP clock speed to 1200MHz like the i7-2635QM or even 1300MHz like the high-end dual and quad cores. Apple generally doesn't like to play Intel's small feature variation games and they've had custom Intel CPUs before to incorporate full-feature sets like VT support which Intel tends to drop from their low-clock speed CPUs, so there is precedent for this.
     
  10. Evil Spoonman thread starter macrumors 6502

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    Jan 21, 2011
    Location:
    California
    #10
    Great information, commander.data. I agree with everything you've said here and have updated the first post to reflect it. I would bet on 1300MHz to bring it to parity with the 2620M. Apple probably, as you say, doesn't care so much about 100MHz on the 15" as it has a dGPU, and it was cheaper to find a closest-match off the shelf part.
     

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