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GeForce GT 640 DDR3 vs GeForce GTX 460

Intro

The GeForce GT 640 DDR3 has a clock speed of 900 MHz and a DDR3 memory speed of 1782 MHz. It also uses a 128-bit memory bus, and uses a 28 nm design. It features 384 SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

Compare all of that to the GeForce GTX 460, which makes use of a 40 nm design. nVidia has set the core speed at 675 MHz. The GDDR5 RAM is set to run at a frequency of 900 MHz on this particular card. It features 336 SPUs along with 56 Texture Address Units and 24 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3 65 Watts
GeForce GTX 460 150 Watts
Difference: 85 Watts (131%)

Memory Bandwidth

In theory, the GeForce GTX 460 should be a lot faster than the GeForce GT 640 DDR3 overall. (explain)

GeForce GTX 460 86400 MB/sec
GeForce GT 640 DDR3 57024 MB/sec
Difference: 29376 (52%)

Texel Rate

The GeForce GTX 460 should be a lot (more or less 31%) more effective at AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 460 37800 Mtexels/sec
GeForce GT 640 DDR3 28800 Mtexels/sec
Difference: 9000 (31%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 460 is superior to the GeForce GT 640 DDR3, not by a very large margin though. (explain)

GeForce GTX 460 16200 Mpixels/sec
GeForce GT 640 DDR3 14400 Mpixels/sec
Difference: 1800 (13%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

GeForce GT 640 DDR3

Amazon.com

GeForce GTX 460

Amazon.com

Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.

Specifications

Model GeForce GT 640 DDR3 GeForce GTX 460
Manufacturer nVidia nVidia
Year June 2012 July 2010
Code Name GK107 GF104
Fab Process 28 nm 40 nm
Bus PCIe 3.0 x16 PCIe x16
Memory 2048 MB 768 MB
Core Speed 900 MHz 675 MHz
Shader Speed 900 MHz 1350 MHz
Memory Speed 1782 MHz (3564 MHz effective) 900 MHz (3600 MHz effective)
Unified Shaders 384 336
Texture Mapping Units 32 56
Render Output Units 16 24
Bus Type DDR3 GDDR5
Bus Width 128-bit 192-bit
DirectX Version DirectX 11.0 DirectX 11
OpenGL Version OpenGL 4.2 OpenGL 4.1
Power (Max TDP) 65 watts 150 watts
Shader Model 5.0 5.0
Bandwidth 57024 MB/sec 86400 MB/sec
Texel Rate 28800 Mtexels/sec 37800 Mtexels/sec
Pixel Rate 14400 Mpixels/sec 16200 Mpixels/sec

Memory Bandwidth: Bandwidth is the max amount of data (in units of megabytes per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total texture units by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.

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