Compare any two graphics cards:
Radeon HD 7870 XT vs Radeon R9 270X
IntroThe Radeon HD 7870 XT has a GPU clock speed of 925 MHz, and the 2048 MB of GDDR5 memory is set to run at 1500 MHz through a 256-bit bus. It also is comprised of 1536 SPUs, 96 Texture Address Units, and 32 ROPs.
Compare all of that to the Radeon R9 270X, which comes with GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 1400 MHz through a 256-bit bus. It also features 1280 Stream Processors, 80 TAUs, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7870 XT should be 7% quicker than the Radeon R9 270X overall, due to its greater bandwidth. (explain)
Texel RateThe Radeon HD 7870 XT should be a small bit (more or less 11%) better at AF than the Radeon R9 270X. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the Radeon R9 270X is the winner, though not by far. (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 largest amount of information (measured in megabytes per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 amount 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 clock speed of the chip. The better the texel rate, the better the graphics 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 most pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.