Compare any two graphics cards:
GeForce GTX 285 1GB vs Radeon HD 4890 1GB
IntroThe GeForce GTX 285 1GB has a GPU clock speed of 648 MHz, and the 1024 MB of GDDR3 memory is set to run at 1242 MHz through a 512-bit bus. It also is made up of 240 Stream Processors, 80 Texture Address Units, and 32 ROPs.
Compare that to the Radeon HD 4890 1GB, which comes with a core clock frequency of 1000 MHz and a GDDR5 memory speed of 975 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the GeForce GTX 285 1GB should in theory be quite a bit superior to the Radeon HD 4890 1GB in general. (explain)
Texel RateThe GeForce GTX 285 1GB should be much (about 30%) more effective at texture filtering than the Radeon HD 4890 1GB. (explain)
Pixel RateThe GeForce GTX 285 1GB will be much (about 30%) better at full screen anti-aliasing than the Radeon HD 4890 1GB, and also able to handle higher screen resolutions without slowing down too much. (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: Bandwidth is the max amount of data (counted in megabytes per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.