GeForce GT 640 DDR3 vs Radeon RX 480 4GB

Intro

Compare that to the Radeon RX 480 4GB, which uses a 14 nm design. AMD has clocked the core frequency at 1120 MHz. The GDDR5 memory works at a speed of 1750 MHz on this particular card. It features 2304 SPUs along with 144 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon RX 480 4GB		150 Watts
	Difference: 85 Watts (131%)

Memory Bandwidth

In theory, the Radeon RX 480 4GB will be 302% faster than the GeForce GT 640 DDR3 overall, because of its higher data rate. (explain)

Radeon RX 480 4GB		229376 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 172352 (302%)

Texel Rate

The Radeon RX 480 4GB should be a lot (more or less 460%) better at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon RX 480 4GB		161280 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 132480 (460%)

Pixel Rate

If using a high resolution is important to you, then the Radeon RX 480 4GB is a better choice, by a large margin. (explain)

Radeon RX 480 4GB		35840 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 21440 (149%)

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 largest amount of data (counted in MB per second) that can be transferred past the external memory interface within a second. The number is calculated by multiplying the interface width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 once again. If 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 high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.