NVIDIA GeForce GT 640M

NVIDIA GeForce GT 640M

The NVIDIA GeForce GT 640M is a mid-range, DirectX 11.1 compatible graphics card that was announced in the first quarter of 2012 for laptops. It is a Kepler-based GPU built on the GK107 architecture and is manufactured in 28nm at TSMC. The graphics card uses a 128-Bit wide memory interface with either the more common but slower DDR3 for VRAM or the more expensive and faster GDDR5.


The Kepler architecture is the successor to the Fermi architecture that first appeared in laptops with the GeForce 400M series. The GK107 Kepler core offers two shader blocks, called SMX, each with 192 shaders for a total of 384 shader cores that are clocked at the same speed as the processor core. Although more shader cores are available in the Kepler architecture as compared to the Fermi design, the Kepler shaders are still expected to be up to twice as power efficient. However, due to the missing hot clock of the shader domain, two shaders of a Kepler chip are as fast as one shader of a Fermi chip (the latter is clocked twice as fast). PCIe 3.0 is now supported by the mobile Kepler series and an optional Turbo mode can automatically overclock the Nvidia card by a theoretical 15 percent if the laptop cooling system allows it. The implementation of this boost mode is done in the BIOS, but it is ultimately dependent upon the manufacturer of the laptop.


The gaming performance of the GeForce GT 640M equipped with DDR3 graphics memory lies somewhere in the former 2011 high-end category between the older GeForce GT 555M and GeForce GTX 460M. The performance is exceptionally good in shader-heavy DirectX 11 games and benchmarks. However, the 128-Bit memory interface can be a bottleneck if DDR3 graphics memory is used. In our tests, demanding games of 2011 like Battlefield 3 are playable in 1366x768 and medium settings. Less demanding games, such as Modern Warfare 3, are easily playable with maxed out settings and high resolutions. Details on synthetic and gaming benchmarks performances of the GT 640M can be seen below. The more uncommon GDDR5 version of the GT 640M is slightly faster, getting closer to the DDR3 version of the GT 650M.


The improved feature set now includes support for up to 4 active displays. Furthermore, high resolution monitors of up to 3840x2160 pixels can now be connected using DisplayPort 1.2 or HDMI 1.4a if available. HD-Audio codecs, such as Dolby TrueHD and DTS-HD, can be transmitted via bitstream mode through the HDMI port. However, as most laptops will feature Optimus, the integrated GPU will likely have direct control over the display ports and may limit the feature set available by the Nvidia Kepler cards.

The 5th generation PureVideo HD video processor (VP5) is also integrated in the GK107 core and offers hardware decoding of HD videos. Common codecs such as MPEG-1/2, MPEG-4 ASP, H.264 and VC1/WMV9 are fully supported up to 4K resolutions while VC1 and MPEG-4 are supported up to 1080p. Two streams can be decoded in parallel for features such as Picture-in-Picture. Another novelty is the inclusion of a dedicated video encoding engine similar to Intel QuickSync that can be accessed by the NVENCI API.

The power consumption of the GeForce GT 640M is a bit below that of the older GeForce GT 540M and more in line with the GT 525M. As a result, the Nvidia GPU is best suited for multimedia notebooks 14-inches or greater.

GeForce GT 600M Series
GeForce GT 650M SLI (compare) 768 @ 790 - 835 (Boost) MHz2x 128 Bit @ 4000 MHz
GeForce GT 650M (compare) 384 @ 735 - 900 (Boost) MHz128 Bit @ 1800 - 4000 MHz
GeForce GT 645M (compare) 384 @ 710 MHz128 Bit @ 1800 MHz
GeForce GT 640M 384 @ 625 - 645 (Boost) MHz128 Bit @ 1800 - 4000 MHz
GeForce GT 640M LE (compare) 384 @ 500 MHz128 Bit @ 1800 - 4000 MHz
GeForce GT 635M (compare) 144 @ 660 - 753 (Boost) MHz128/192 Bit @ 1800 MHz
GeForce GT 630M (compare) 96 @ 672 MHz128 Bit @ 1800 MHz
GeForce GT 625M (compare) 96 @ 625 MHz64 Bit @ 1800 MHz
GeForce GT 620M (compare) 96 @ 625 - 715 (Boost) MHz64 / 128 Bit @ 1800 MHz
Pipelines384 - unified
Core Speed625 - 645 (Boost) MHz
Memory Speed1800 - 4000 MHz
Memory Bus Width128 Bit
Memory TypeDDR3, GDDR5
Max. Amount of Memory2048 MB
Shared Memoryno
DirectXDirectX 11, Shader 5.0
technology28 nm
FeaturesOptimus, PhysX, Verde Drivers, CUDA, 3D Vision, 3DTV Play
Notebook Sizemedium sized
Date of Announcement22.03.2012


3DMark 11 - Performance 1280x720
min: 1691     avg: 1854.9     median: 1860.5 (6%)     max: 1968 points
3DMark 11 - Performance GPU 1280x720
min: 1534     avg: 1708.3     median: 1728 (3%)     max: 1778 points
3DMark Vantage
P Result 1280x1024 +
P GPU no PhysX 1280x1024 +
3DMark 03 - Standard 1024x768
min: 28232     avg: 29495     median: 29298.5 (16%)     max: 31151 Points
3DMark 05 - Standard 1024x768
min: 15287     avg: 17104.8     median: 16784 (36%)     max: 19564 Points
3DMark 06 Standard 1280x1024 +
Unigine Heaven 2.1 - high, Tesselation (normal), DirectX11 1280x1024
min: 22.5     avg: 23.9     median: 23.5 (10%)     max: 26 fps
SPECviewperf 11
Siemens NX 1920x1080 +
Tcvis 1920x1080 +
SolidWorks 1920x1080 +
Pro/ENGINEER 1920x1080 +
Maya 1920x1080 +
Lightwave 1920x1080 +
Ensight 1920x1080 +
Catia 1920x1080 +
Windows 7 Experience Index - Gaming graphics
min: 6.7     avg: 6.9     median: 6.9 (87%)     max: 7 points
Windows 7 Experience Index - Graphics
min: 4.6     avg: 6.3     median: 6.9 (87%)     max: 7 points
Cinebench R10 Shading 32Bit +
Cinebench R11.5 OpenGL 64Bit +
Cinebench R15
OpenGL 64Bit +
Ref. Match 64Bit +
- Range of benchmark values for this graphics card
- Average benchmark values for this graphics card
* Smaller numbers mean a higher performance

Game Benchmarks

The following benchmarks stem from our benchmarks of review laptops. The performance depends on the used graphics memory, clock rate, processor, system settings, drivers, and operating systems. So the results don't have to be representative for all laptops with this GPU. For detailled information on the benchmark results, click on the fps number.

Team Fortress 2

Team Fortress 2

low 1280x720
59.3  fps    + Compare
» With all tested laptops playable in detail settings low.
Farming Simulator 17
low 1280x720
83  fps    + Compare
med. 1366x768
50.9  fps    + Compare
high 1920x1080
22.6  fps    + Compare
» With all tested laptops playable in detail settings med..
Mirror's Edge Catalyst
low 1280x720
34  fps    + Compare
med. 1366x768
18.6  fps    + Compare
» The benchmarks indicate that the game is not playable in the tested settings.


low 1280x720
52  fps    + Compare
med. 1366x768
44.7  fps    + Compare
high 1920x1080
22.1  fps    + Compare
» With all tested laptops playable in detail settings med..
Far Cry Primal
low 1280x720
21  fps    + Compare
med. 1920x1080
10  fps    + Compare
» The benchmarks indicate that the game is not playable in the tested settings.
Rainbow Six Siege
low 1024x768
51.4  fps    + Compare
med. 1366x768
29.2  fps    + Compare
high 1920x1080
16.5  fps    + Compare