Compare any two graphics cards:
Geforce GTX 770 vs Radeon HD 7990
IntroThe Geforce GTX 770 makes use of a 28 nm design. nVidia has clocked the core frequency at 1046 MHz. The GDDR5 RAM works at a speed of 1753 MHz on this model. It features 1536 SPUs along with 128 Texture Address Units and 32 ROPs.
Compare that to the Radeon HD 7990, which uses a 28 nm design. AMD has clocked the core frequency at 950 MHz. The GDDR5 memory is set to run at a frequency of 1500 MHz on this card. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 7990 should perform quite a bit faster than the Geforce GTX 770 overall. (explain)
Texel RateThe Radeon HD 7990 is quite a bit (more or less 82%) more effective at texture filtering than the Geforce GTX 770. (explain)
Pixel RateThe Radeon HD 7990 should be much (about 82%) better at FSAA than the Geforce GTX 770, and should be capable of handling higher 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.
Geforce GTX 770
Radeon HD 7990
Memory Bandwidth: Memory bandwidth is the max amount of data (measured in MB per second) that can be transferred across the external memory interface in a second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster 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 number of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total texture units of the card by the core 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 in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines 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 is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.
Geforce GTX 770
Radeon HD 7990