Compare any two graphics cards:
Radeon HD 4850 X2 512MB vs Radeon R9 M270X
IntroThe Radeon HD 4850 X2 512MB features a GPU core clock speed of 625 MHz, and the 512 MB of GDDR3 RAM is set to run at 993 MHz through a 256-bit bus. It also features 800(160x5) Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.
Compare those specifications to the Radeon R9 M270X, which features clock speeds of 725 MHz on the GPU, and 1125 MHz on the 2048 MB of GDDR5 memory. It features 640 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Theoretically speaking, the Radeon HD 4850 X2 512MB should be a lot faster than the Radeon R9 M270X overall. (explain)
Texel RateThe Radeon HD 4850 X2 512MB is a lot (about 72%) faster with regards to anisotropic filtering than the Radeon R9 M270X. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the Radeon HD 4850 X2 512MB is a better choice, 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.
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.
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 max amount of data (measured in megabytes per second) that can be transferred past the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is calculated by multiplying the total amount of texture units by the core clock 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 in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.