Compare any two graphics cards:
GeForce 9500 GT 1GB GDDR3 vs Radeon HD 6750
IntroThe GeForce 9500 GT 1GB GDDR3 has a GPU core clock speed of 550 MHz, and the 1024 MB of GDDR3 RAM is set to run at 800 MHz through a 128-bit bus. It also features 32 Stream Processors, 16 Texture Address Units, and 8 ROPs.
Compare that to the Radeon HD 6750, which has core clock speeds of 725 MHz on the GPU, and 1000 MHz on the 512 MB of GDDR5 memory. It features 720 SPUs along with 36 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6750 should be 150% faster than the GeForce 9500 GT 1GB GDDR3 overall, because of its higher data rate. (explain)
Texel RateThe Radeon HD 6750 is much (about 197%) better at anisotropic filtering than the GeForce 9500 GT 1GB GDDR3. (explain)
Pixel RateIf running with a high resolution is important to you, then the Radeon HD 6750 is superior to the GeForce 9500 GT 1GB GDDR3, 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.
Memory Bandwidth: Memory bandwidth is the maximum amount of data (counted in megabytes per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the bus width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units 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 rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.