Compare any two graphics cards:
Geforce GTX 770 vs Radeon HD 7990
IntroThe Geforce GTX 770 features a core clock speed of 1046 MHz and a GDDR5 memory speed of 1753 MHz. It also uses a 256-bit bus, and makes use of a 28 nm design. It is comprised of 1536 SPUs, 128 TAUs, and 32 ROPs.
Compare those specifications to the Radeon HD 7990, which has a core clock speed of 950 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 384-bit memory bus, and uses a 28 nm design. It is made up of 2048 SPUs, 128 TAUs, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7990 should perform much faster than the Geforce GTX 770 overall. (explain)
Texel RateThe Radeon HD 7990 should be much (about 82%) better at AF than the Geforce GTX 770. (explain)
Pixel RateIf using high levels of AA is important to you, then the Radeon HD 7990 is a better choice, and very much so. (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 data (counted in MB per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.