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GeForce GT 640 DDR3 vs GeForce GTX 460

Intro

The GeForce GT 640 DDR3 has core speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 memory. It features 384 SPUs as well as 32 Texture Address Units and 16 ROPs.

Compare that to the GeForce GTX 460, which has GPU clock speed of 675 MHz, and 768 MB of GDDR5 memory set to run at 900 MHz through a 192-bit bus. It also is made up of 336 SPUs, 56 Texture Address Units, and 24 Raster Operation 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

Theoretically speaking, the GeForce GTX 460 should perform 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 is much (more or less 31%) better at texture filtering 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 using high levels of AA is important to you, then the GeForce GTX 460 is a better choice, though only just barely. (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: Memory bandwidth is the max amount of information (in units of MB per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling 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 could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs 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 lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.

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