Compare any two graphics cards:
GeForce GTX 870M vs Radeon R9 M385X
IntroThe GeForce GTX 870M comes with core speeds of 941 MHz on the GPU, and 1000 MHz on the 3072 MB of GDDR5 memory. It features 1344 SPUs as well as 112 TAUs and 24 ROPs.
Compare those specs to the Radeon R9 M385X, which features a GPU core clock speed of 1100 MHz, and 4096 MB of GDDR5 RAM running at 1500 MHz through a 128-bit bus. It also is made up of 896 SPUs, 56 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Both cards have exactly the same bandwidth, so theoretically they should perform exactly the same. (explain)
Texel RateThe GeForce GTX 870M should be much (about 71%) better at anisotropic filtering than the Radeon R9 M385X. (explain)
Pixel RateThe GeForce GTX 870M should be quite a bit (more or less 28%) better at anti-aliasing than the Radeon R9 M385X, and also should be capable of handling higher screen resolutions while still performing well. (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.
Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.
Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.