GeForce GT 240 GDDR5 vs GeForce GT 640 DDR3

Intro

Compare those specs to the GeForce GT 640 DDR3, which uses a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 memory works at a speed of 1782 MHz on this card. It features 384 SPUs along with 32 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GT 240 GDDR5		70 Watts
	Difference: 5 Watts (8%)

Memory Bandwidth

Theoretically speaking, the GeForce GT 640 DDR3 will be 5% quicker than the GeForce GT 240 GDDR5 in general, because of its higher data rate. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce GT 240 GDDR5		54400 MB/sec
	Difference: 2624 (5%)

Texel Rate

The GeForce GT 640 DDR3 should be much (more or less 64%) more effective at AF than the GeForce GT 240 GDDR5. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GT 240 GDDR5		17600 Mtexels/sec
	Difference: 11200 (64%)

Pixel Rate

If using a high resolution is important to you, then the GeForce GT 640 DDR3 is a better choice, by a large margin. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GT 240 GDDR5		4400 Mpixels/sec
	Difference: 10000 (227%)

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

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (counted in megabytes per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. If the card has 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 AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.