GeForce GT 640 DDR3 vs Radeon RX 470 4GB

Intro

Compare that to the Radeon RX 470 4GB, which features a clock frequency of 926 MHz and a GDDR5 memory speed of 1650 MHz. It also features a 256-bit bus, and uses a 14 nm design. It is made up of 2048 SPUs, 128 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 470 4GB		120 Watts
	Difference: 55 Watts (85%)

Memory Bandwidth

As far as performance goes, the Radeon RX 470 4GB should theoretically be much superior to the GeForce GT 640 DDR3 in general. (explain)

Radeon RX 470 4GB		211200 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 154176 (270%)

Texel Rate

The Radeon RX 470 4GB will be a lot (about 312%) better at texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon RX 470 4GB		118528 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 89728 (312%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon RX 470 4GB is superior to the GeForce GT 640 DDR3, by a large margin. (explain)

Radeon RX 470 4GB		29632 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 15232 (106%)

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: Memory bandwidth is the max amount of information (counted in MB per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. 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 high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the card's clock speed. 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 rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.