Compare any two graphics cards:
GeForce GTX 285 1GB vs Radeon HD 4890 1GB
IntroThe GeForce GTX 285 1GB comes with a GPU core speed of 648 MHz, and the 1024 MB of GDDR3 RAM is set to run at 1242 MHz through a 512-bit bus. It also features 240 SPUs, 80 Texture Address Units, and 32 ROPs.
Compare those specs to the Radeon HD 4890 1GB, which comes with GPU core speed of 1000 MHz, and 1024 MB of GDDR5 RAM set to run at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 285 1GB should be 27% quicker than the Radeon HD 4890 1GB overall, because of its greater data rate. (explain)
Texel RateThe GeForce GTX 285 1GB is quite a bit (more or less 30%) more effective at AF than the Radeon HD 4890 1GB. (explain)
Pixel RateThe GeForce GTX 285 1GB is a lot (approximately 30%) more effective at AA than the Radeon HD 4890 1GB, and capable of handling higher screen resolutions without losing too much performance. (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 (in units of MB per second) that can be moved across the external memory interface in one second. It's worked out by multiplying the bus width by its memory speed. If the card has DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 amount of texture map elements (texels) that are processed in one second. This number is worked out 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 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 maximum amount of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.