Compare any two graphics cards:
Radeon HD 4870 2GB vs Radeon RX 460
IntroThe Radeon HD 4870 2GB features a GPU core 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) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon RX 460, which comes with a core clock frequency of 1090 MHz and a GDDR5 memory speed of 1750 MHz. It also makes use of a 128-bit memory bus, and uses a 14 nm design. It is made up of 896 SPUs, 56 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 4870 2GB should in theory be just a bit better than the Radeon RX 460 in general. (explain)
Texel RateThe Radeon RX 460 will be quite a bit (more or less 103%) faster with regards to AF than the Radeon HD 4870 2GB. (explain)
Pixel RateIf using a high screen resolution 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: Bandwidth is the max amount of information (counted in megabytes per second) that can be moved across the external memory interface in a second. It is calculated by multiplying the bus width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This is worked out by multiplying the total texture units by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum number of pixels the video 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 amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few 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.