Discussion in 'MacBook Pro' started by cclloyd, Dec 10, 2013.

  1. cclloyd macrumors 68000


    Oct 26, 2011
    Alpha Centauri A
    Does anyone know how many FLOPs the early 2013 15" rMBP gets? I was looking, and the only site I found that told the flops of the GT 650m was the wrong card. I could tell cause it only had DDR3, not GDDR5 memory. So does anyone know where I can get full specs and performance on the card?
  2. sonyisawesome macrumors regular

    Jul 24, 2012
    650M on last model's 15" rmbp is gddr5, not ddr3.
  3. leman, Dec 11, 2013
    Last edited: Dec 11, 2013

    leman macrumors G3

    Oct 14, 2008
    The VRAM speed has no influence on the FLOPs. Kepler GPUs give you 2 FLOPS per core per clock. Now, i have no idea how the 750M in the 2013 is clocked, but assuming the standard 967Mhz, the total FLOPs for 384 cores should be around 740 GFLOPs or so. In addition, with the base 2.0 GHz Haswell CPU, you get the Iris Pro with around 780 GFLOPs and the CPU itself also offers around 128 GFLOPs (correction: its 256 GFLOPs) . In total, you are looking at around 1600 GFLOPs.

    Of course, this is just the theoretic peak, in real-life you won't get even close to it. Especially with the 750M.

    Edit: corrected the number for the Haswell CPU
  4. cclloyd thread starter macrumors 68000


    Oct 26, 2011
    Alpha Centauri A
    I said that it should be GDDR5....

    Also my 2013 model is the 650M, early 2013, not the 750m. Does anyone know what real world performance increase the 750m has over it?
  5. theSeb macrumors 604


    Aug 10, 2010
    Poole, England
    Performance increase in what? There is no uniform performance increase that we can tell you and FLOPS is not going to tell you much. You need to be more specific when asking about performance increases and include the context.

    However that the big caveat is the first bit about clock speed. We know that the 650M was slightly over-clocked. I do not know what the clock speed is of the 750M in the 2013 MBP. This review also focuses on the DDR3, whereas the MBP has the GDDR version. So that will make a bit of a difference, depending on the activity.

  6. durkkin macrumors regular

    Sep 23, 2013
    Why does the FLOPS matter? Pretty much always the CPU/GPU is going to outperform the read/write speed of whatever is feeding instruction.
  7. leman macrumors G3

    Oct 14, 2008
    Oh, sorry, I didn't catch that. For the first-yen rMBP:

    650M at around 700 Gflops, the CPU at around 150GFLOPs and the HD4000 with 294.4 GFLOPs. BTW, i made a mistake in my previous post - the Haswell CPU FLOPS should be doubled.

    Why are you asking anyway?


    around 5% depending on the application, maybe slightly more.
  8. dusk007 macrumors 68040


    Dec 5, 2009
    At default clock the 750M is 2.7% faster because it is clocked by Apple at 925Mhz while the 650M was clocked at 900Mhz.
    In reality the extra 1GB of VRAM helps performance at settings the 650M with 1GB will not run at all or with a much steeper performance decline. Or visual bugs.
    The 750M is likely to run somewhat cooler at similar clock speeds as it is usually clocked much higher and expected to run at 1060Mhz (only Apple clocks it so low) while the 650M with GDDR5 was expected to run around 850Mhz (Apple clocked it higher). But that is hard to quantify as 650Ms produced very recently will probably run just as cool as the 750M while those produced many months ago will not.

    FLOPS are rather meaningless as the memory bandwidth really doesn't affect the calculation at all, while it certainly does actual performance.

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