Compare any two graphics cards:
Geforce GTX 770 vs Radeon HD 7990
IntroThe Geforce GTX 770 comes with a GPU core clock speed of 1046 MHz, and the 2048 MB of GDDR5 RAM runs at 1753 MHz through a 256-bit bus. It also is comprised of 1536 Stream Processors, 128 TAUs, and 32 ROPs.
Compare all that to the Radeon HD 7990, which uses a 28 nm design. AMD has clocked the core speed at 950 MHz. The GDDR5 memory runs at a frequency of 1500 MHz on this card. It features 2048 SPUs as well as 128 TAUs 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 better than the Geforce GTX 770 overall. (explain)
Texel RateThe Radeon HD 7990 will be quite a bit (about 82%) faster with regards to texture filtering than the Geforce GTX 770. (explain)
Pixel RateThe Radeon HD 7990 is much (approximately 82%) faster with regards to FSAA than the Geforce GTX 770, and also will be able to handle higher screen 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.
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 max amount of information (counted in MB per second) that can be transported past the external memory interface in a second. The number is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR type memory, it must 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 high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.