Compare any two graphics cards:
Radeon HD 3850 512MB vs Radeon HD 4850 2GB
IntroThe Radeon HD 3850 512MB features a clock speed of 668 MHz and a GDDR3 memory speed of 828 MHz. It also uses a 256-bit memory bus, and makes use of a 55 nm design. It features 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.
Compare those specifications to the Radeon HD 4850 2GB, which comes with GPU clock speed of 625 MHz, and 2048 MB of GDDR4 memory set to run at 993 MHz through a 256-bit bus. It also is made up of 800(160x5) Stream Processors, 40 TAUs, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 4850 2GB should in theory be a small bit superior to the Radeon HD 3850 512MB in general. (explain)
Texel RateThe Radeon HD 4850 2GB should be quite a bit (approximately 134%) better at anisotropic filtering than the Radeon HD 3850 512MB. (explain)
Pixel RateThe Radeon HD 3850 512MB should be a bit (more or less 7%) more effective at anti-aliasing than the Radeon HD 4850 2GB, and also will be 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: Bandwidth is the max amount of data (in units of MB per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the 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 video card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the clock speed of the card. 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 is also dependant 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.