Compare any two graphics cards:
Radeon HD 4850 512MB vs Radeon HD 6750
IntroThe Radeon HD 4850 512MB makes use of a 55 nm design. AMD has clocked the core frequency at 625 MHz. The GDDR3 memory works at a frequency of 993 MHz on this particular card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.
Compare those specs to the Radeon HD 6750, which uses a 40 nm design. AMD has clocked the core frequency at 725 MHz. The GDDR5 RAM is set to run at a speed of 1000 MHz on this particular card. It features 720 SPUs along with 36 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 6750 should theoretically be a bit better than the Radeon HD 4850 512MB overall. (explain)
Texel RateThe Radeon HD 6750 is a bit (more or less 4%) better at AF than the Radeon HD 4850 512MB. (explain)
Pixel RateThe Radeon HD 6750 should be just a bit (more or less 16%) more effective at FSAA than the Radeon HD 4850 512MB, and will be capable of handling higher screen resolutions more effectively. (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 largest amount of information (in units of megabytes per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is worked out by multiplying the total number of texture units by the core clock 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 in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.