Compare any two graphics cards:
GeForce GTX 460 2GB vs Radeon HD 4870 512MB
IntroThe GeForce GTX 460 2GB has clock speeds of 675 MHz on the GPU, and 900 MHz on the 2048 MB of GDDR5 RAM. It features 336 SPUs along with 56 TAUs and 32 Rasterization Operator Units.
Compare all that to the Radeon HD 4870 512MB, which comes with core speeds of 750 MHz on the GPU, and 900 MHz on the 512 MB of GDDR5 memory. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have exactly the same memory bandwidth, so theoretically they should perform the same. (explain)
Texel RateThe GeForce GTX 460 2GB should be a lot (more or less 26%) faster with regards to AF than the Radeon HD 4870 512MB. (explain)
Pixel RateThe GeForce GTX 460 2GB will be a lot (approximately 80%) more effective at AA than the Radeon HD 4870 512MB, and also should be able to handle higher screen 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.
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 max amount of data (counted in megabytes per second) that can be transported over 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 the card has DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.