GeForce GT 440 3GB vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which has clock speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 RAM. It features 384 SPUs as well as 32 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 440 3GB		56 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 9 Watts (16%)

Memory Bandwidth

As far as performance goes, the GeForce GT 640 DDR3 should in theory be much better than the GeForce GT 440 3GB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce GT 440 3GB		43200 MB/sec
	Difference: 13824 (32%)

Texel Rate

The GeForce GT 640 DDR3 should be a lot (about 102%) better at AF than the GeForce GT 440 3GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GT 440 3GB		14256 Mtexels/sec
	Difference: 14544 (102%)

Pixel Rate

The GeForce GT 640 DDR3 should be just a bit (approximately 1%) faster with regards to anti-aliasing than the GeForce GT 440 3GB, and capable of handling higher screen resolutions without slowing down too much. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GT 440 3GB		14256 Mpixels/sec
	Difference: 144 (1%)

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 data (counted in megabytes per second) that can be transported past the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.