Compare any two graphics cards:
GeForce GTX 285 1GB vs Radeon HD 4890 1GB
IntroThe GeForce GTX 285 1GB has a GPU core clock 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 Stream Processors, 80 TAUs, 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 memory set to run at 975 MHz through a 256-bit bus. It also features 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GTX 285 1GB should in theory perform a lot faster than the Radeon HD 4890 1GB overall. (explain)
Texel RateThe GeForce GTX 285 1GB will be a lot (approximately 30%) more effective at anisotropic filtering than the Radeon HD 4890 1GB. (explain)
Pixel RateThe GeForce GTX 285 1GB should be a lot (approximately 30%) better at AA than the Radeon HD 4890 1GB, and able to handle 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.
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 (in units of megabytes per second) that can be moved over the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure 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 video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.