Compare any two graphics cards:
Radeon HD 4870 1GB vs Radeon HD 6870
IntroThe Radeon HD 4870 1GB comes with clock speeds of 750 MHz on the GPU, and 900 MHz on the 1024 MB of GDDR5 RAM. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.
Compare all of that to the Radeon HD 6870, which features clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 1120 SPUs along with 56 Texture Address Units and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 6870 should in theory be just a bit superior to the Radeon HD 4870 1GB in general. (explain)
Texel RateThe Radeon HD 6870 is much (more or less 68%) faster with regards to anisotropic filtering than the Radeon HD 4870 1GB. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 6870 is superior to the Radeon HD 4870 1GB, 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.
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 MB per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling 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 its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.