Compare any two graphics cards:
Radeon HD 4870 2GB vs Radeon R9 M385X
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 comprised of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 ROPs.
Compare all of that to the Radeon R9 M385X, which uses a 28 nm design. AMD has clocked the core speed at 1100 MHz. The GDDR5 RAM works at a speed of 1500 MHz on this specific card. It features 896 SPUs along with 56 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Performance-wise, the Radeon HD 4870 2GB should in theory be just a bit better than the Radeon R9 M385X overall. (explain)
Texel RateThe Radeon R9 M385X is a lot (more or less 105%) better at anisotropic filtering than the Radeon HD 4870 2GB. (explain)
Pixel RateThe Radeon R9 M385X should be much (approximately 47%) faster with regards to FSAA than the Radeon HD 4870 2GB, and should be capable of handling higher resolutions without slowing down too much. (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 data (in units of megabytes per second) that can be transferred across the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. The number 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 drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.