Compare any two graphics cards:
Radeon HD 4750 vs Radeon HD 4830 512MB
IntroThe Radeon HD 4750 comes with a GPU clock speed of 730 MHz, and the 512 MB of GDDR5 RAM runs at 800 MHz through a 128-bit bus. It also features 640(128x5) Stream Processors, 32 TAUs, and 16 ROPs.
Compare all of that to the Radeon HD 4830 512MB, which has core speeds of 575 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 memory. It features 640(128x5) SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 4830 512MB should in theory perform a bit faster than the Radeon HD 4750 in general. (explain)
Texel RateThe Radeon HD 4750 is much (approximately 27%) better at anisotropic filtering than the Radeon HD 4830 512MB. (explain)
Pixel RateThe Radeon HD 4750 is quite a bit (approximately 27%) more effective at FSAA than the Radeon HD 4830 512MB, and should be able to handle higher resolutions better. (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.
Memory Bandwidth: Bandwidth is the maximum amount of data (measured in megabytes per second) that can be moved across the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster 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 number of 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 higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.