HWBench.com

    GeForce GT 640M vs GeForce 840M

    GeForce GT 640M
    Memory: 2048Mb DDR3MOBILE
    Release date: 22 Mar 2012
    GeForce GT 640M
    GeForce 840M
    Memory: 1024Mb DDR3MOBILE
    Release date: 12 Mar 2014
    GeForce 840M

    Summary

    Synthetic performance index

    • GeForce GT 640M
      100%
    • GeForce 840M
      137%

    Relative performance

    Reasons to consider GeForce GT 640M

    Supports PhysX
    Supports G-Sync
    Supports ShadowPlay (allows game streaming/recording with minimum performance penalty)
    Based on an outdated architecture (Nvidia Kepler), there are less performance optimizations for current games and applications

    Reasons to consider GeForce 840M

    This is a much newer product, it might have better long term support.
    Around 37% higher average synthetic performance.
    Supports PhysX
    Supports G-Sync
    Supports ShadowPlay (allows game streaming/recording with minimum performance penalty)
    Based on an outdated architecture (Nvidia Maxwell), there may be no performance optimizations for current games and applications
    GeForce 840M

    HWBench recommends GeForce 840M

    The GeForce 840M is the better performing card based on the synthetic benchmarks used (1 benchmarks).

    Specifications

    Core Configuration

    GeForce GT 640MGeForce 840M
    GPU NameGK107 (N13P-GS)vsGM108 (N15S-GT)
    Fab Process28 nmvs28 nm
    Die Size118 mm²vs0 mm²
    Transistors1,270 millionvsunknown
    Shaders384vs384
    Compute Units2vs3
    Core clock625 MHzvs1029 MHz
    ROPs16vs8
    TMUs32vs16

    Memory Configuration

    GeForce GT 640MGeForce 840M
    Memory TypeDDR3vsDDR3
    Bus Width128 bitvs64 bit
    Memory Speed900 MHz
    1800 MHz effective    		vs1001 MHz
    2002 MHz effective
    Memory Size2048 Mbvs1024 Mb

    Additional details

    GeForce GT 640MGeForce 840M
    TDP32 wattsvs33 watts
    Release Date22 Mar 2012vs12 Mar 2014

    Raw Performance comparison

    Pixel Rate

    • GeForce GT 640M
      5.00 GP/s
    • GeForce 840M
      8.23 GP/s

    GigaPixels - higher is better

    Texel Rate

    • GeForce GT 640M
      20.00 GT/s
    • GeForce 840M
      16.46 GT/s

    GigaTexels - higher is better

    Memory bandwidth

    • GeForce GT 640M
      28.80 GB/s
    • GeForce 840M
      16.02 GB/s

    GB/s - higher is better

    Single precision performance

    • GeForce GT 640M
      480.00 GFLOPs
    • GeForce 840M
      790.30 GFLOPs

    GFLOPs - higher is better

    Synthetic benchmarks

    3DMark 11

    • GeForce GT 640M
      1770
    • GeForce 840M
      2430

    Points (higher is better)

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