Compare any two graphics cards:
Geforce GTX 770 vs Radeon HD 7990
IntroThe Geforce GTX 770 comes with core clock speeds of 1046 MHz on the GPU, and 1753 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs along with 128 TAUs and 32 ROPs.
Compare those specs to the Radeon HD 7990, which uses a 28 nm design. AMD has clocked the core frequency at 950 MHz. The GDDR5 RAM is set to run at a speed of 1500 MHz on this model. It features 2048 SPUs as well as 128 Texture Address Units and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the Radeon HD 7990 should in theory be a lot superior to the Geforce GTX 770 overall. (explain)
Texel RateThe Radeon HD 7990 should be a lot (about 82%) more effective at AF than the Geforce GTX 770. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 7990 is superior to the Geforce GTX 770, 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: Bandwidth is the max amount of information (measured in MB per second) that can be moved across the external memory interface in a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.