Compare any two graphics cards:
Radeon HD 3870 X2 512MB vs Radeon R9 M275X
IntroThe Radeon HD 3870 X2 512MB comes with a clock frequency of 825 MHz and a GDDR3 memory speed of 900 MHz. It also makes use of a 256-bit memory bus, and uses a 55 nm design. It is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon R9 M275X, which comes with a core clock speed of 900 MHz and a GDDR5 memory frequency of 1125 MHz. It also uses a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
In theory, the Radeon HD 3870 X2 512MB should be a lot faster than the Radeon R9 M275X overall. (explain)
Texel RateThe Radeon R9 M275X should be much (more or less 36%) faster with regards to texture filtering than the Radeon HD 3870 X2 512MB. (explain)
Pixel RateIf running with a high resolution is important to you, then the Radeon HD 3870 X2 512MB is the winner, and very much so. (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 maximum amount of data (in units of megabytes per second) that can be moved over the external memory interface within a second. It's worked out by multiplying the interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better 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 are processed in one second. This figure is worked out by multiplying the total amount of 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 applied per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.