Compare any two graphics cards:
Radeon HD 4850 512MB vs Radeon HD 7850
IntroThe Radeon HD 4850 512MB comes with a GPU core speed of 625 MHz, and the 512 MB of GDDR3 RAM runs at 993 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon HD 7850, which comes with GPU core speed of 860 MHz, and 2048 MB of GDDR5 RAM running at 1200 MHz through a 256-bit bus. It also features 1024 SPUs, 64 TAUs, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 7850 should in theory be much better than the Radeon HD 4850 512MB overall. (explain)
Texel RateThe Radeon HD 7850 should be much (approximately 120%) better at texture filtering than the Radeon HD 4850 512MB. (explain)
Pixel RateIf running with a high resolution is important to you, then the Radeon HD 7850 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.
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: Bandwidth is the maximum amount of data (counted in MB per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the interface width by its memory clock speed. In the case of DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. 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 figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels the video 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 number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.