Compare any two graphics cards:
Radeon HD 4850 512MB vs Radeon HD 7850
IntroThe Radeon HD 4850 512MB features core speeds of 625 MHz on the GPU, and 993 MHz on the 512 MB of GDDR3 RAM. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.
Compare that to the Radeon HD 7850, which features core clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1024 SPUs along with 64 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 7850 should perform a lot faster than the Radeon HD 4850 512MB in general. (explain)
Texel RateThe Radeon HD 7850 should be much (approximately 120%) better at anisotropic filtering than the Radeon HD 4850 512MB. (explain)
Pixel RateThe Radeon HD 7850 should be a lot (more or less 175%) more effective at anti-aliasing than the Radeon HD 4850 512MB, and also capable of handling higher screen resolutions without slowing down too much. (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 (in units of megabytes per second) that can be transported past the external memory interface in a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines 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 is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.