Compare any two graphics cards:
GeForce GTX 580 3GB vs Radeon HD 6770
IntroThe GeForce GTX 580 3GB has a clock speed of 772 MHz and a GDDR5 memory frequency of 1002 MHz. It also makes use of a 384-bit bus, and makes use of a 40 nm design. It features 512 SPUs, 64 TAUs, and 48 Raster Operation Units.
Compare those specs to the Radeon HD 6770, which comes with GPU core speed of 900 MHz, and 512 MB of GDDR5 memory running at 1050 MHz through a 128-bit bus. It also is comprised of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the GeForce GTX 580 3GB should in theory be a lot superior to the Radeon HD 6770 overall. (explain)
Texel RateThe GeForce GTX 580 3GB will be a lot (more or less 37%) more effective at AF than the Radeon HD 6770. (explain)
Pixel RateThe GeForce GTX 580 3GB is quite a bit (approximately 157%) faster with regards to AA than the Radeon HD 6770, and also will be capable of handling higher resolutions while still performing well. (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: Memory bandwidth is the max amount of data (in units of MB per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units 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 rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.