Compare any two graphics cards:
Radeon HD 4750 vs Radeon HD 4830 1GB
IntroThe Radeon HD 4750 comes with a GPU core clock speed of 730 MHz, and the 512 MB of GDDR5 memory runs at 800 MHz through a 128-bit bus. It also features 640(128x5) SPUs, 32 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon HD 4830 1GB, which comes with a core clock frequency of 575 MHz and a GDDR4 memory speed of 900 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It features 640(128x5) SPUs, 32 TAUs, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 4830 1GB will be 13% quicker than the Radeon HD 4750 in general, due to its greater bandwidth. (explain)
Texel RateThe Radeon HD 4750 will be quite a bit (more or less 27%) more effective at anisotropic filtering than the Radeon HD 4830 1GB. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 4750 is superior to the Radeon HD 4830 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 largest amount of information (measured in megabytes per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the bus width by its memory speed. If the card has DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total number 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the card's clock speed. 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 rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.