GeForce GT 640 DDR3 vs Radeon RX 480 4GB

Intro

Compare all that to the Radeon RX 480 4GB, which features core clock speeds of 1120 MHz on the GPU, and 1750 MHz on the 4096 MB of GDDR5 RAM. It features 2304 SPUs as well as 144 Texture Address Units and 32 ROPs.

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

As far as performance goes, the Radeon RX 480 4GB should theoretically be a lot better than the GeForce GT 640 DDR3 overall. (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 (about 460%) more effective at AF 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

The Radeon RX 480 4GB should be quite a bit (approximately 149%) more effective at FSAA than the GeForce GT 640 DDR3, and also should be capable of handling higher resolutions better. (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 max amount of information (counted in MB per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.