Compare any two graphics cards:
Radeon HD 4850 X2 1GB vs Radeon R9 M375X
IntroThe Radeon HD 4850 X2 1GB features a core clock speed of 625 MHz and a GDDR3 memory speed of 993 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon R9 M375X, which has a clock frequency of 1015 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit memory bus, and uses a 28 nm design. It is comprised of 640 SPUs, 40 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
The Radeon HD 4850 X2 1GB should theoretically perform much faster than the Radeon R9 M375X overall. (explain)
Texel RateThe Radeon HD 4850 X2 1GB should be quite a bit (more or less 23%) better at texture filtering than the Radeon R9 M375X. (explain)
Pixel RateThe Radeon HD 4850 X2 1GB is a lot (about 23%) more effective at AA than the Radeon R9 M375X, and will be able to handle higher resolutions without losing too much performance. (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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
Memory Bandwidth: Bandwidth is the largest amount of data (counted in MB per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at 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 that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on 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 bandwidth is, the lower the ability to reach the max fill rate.