Compare any two graphics cards:
Radeon HD 4870 2GB vs Radeon RX 460
IntroThe Radeon HD 4870 2GB has a GPU clock speed of 750 MHz, and the 2048 MB of GDDR5 RAM is set to run at 900 MHz through a 256-bit bus. It also is made up of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon RX 460, which has core clock speeds of 1090 MHz on the GPU, and 1750 MHz on the 4096 MB of GDDR5 memory. It features 896 SPUs as well as 56 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 4870 2GB should be 3% faster than the Radeon RX 460 overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon RX 460 is quite a bit (about 103%) faster with regards to texture filtering than the Radeon HD 4870 2GB. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the Radeon RX 460 is the winner, by a large margin. (explain)
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.
Memory Bandwidth: Memory bandwidth is the largest amount of data (in units of megabytes per second) that can be moved across the external memory interface in 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 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.