Compare any two graphics cards:
GeForce GTX 295 vs Radeon HD 4890 2GB
IntroThe GeForce GTX 295 has a core clock frequency of 576 MHz and a GDDR3 memory frequency of 999 MHz. It also makes use of a 448-bit bus, and makes use of a 55 nm design. It is made up of 240 SPUs, 80 TAUs, and 28 ROPs.
Compare that to the Radeon HD 4890 2GB, which comes with a core clock speed of 1000 MHz and a GDDR5 memory frequency of 975 MHz. It also makes use of a 256-bit bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the GeForce GTX 295 should theoretically be much better than the Radeon HD 4890 2GB in general. (explain)
Texel RateThe GeForce GTX 295 is a lot (about 130%) more effective at AF than the Radeon HD 4890 2GB. (explain)
Pixel RateThe GeForce GTX 295 is much (approximately 102%) better at anti-aliasing than the Radeon HD 4890 2GB, and should be 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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
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 maximum amount of information (measured in megabytes per second) that can be transferred past the external memory interface in a second. It is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once 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 anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.