Compare any two graphics cards:
Radeon HD 7990 vs Radeon R9 290X
IntroThe Radeon HD 7990 features a GPU core clock speed of 950 MHz, and the 3072 MB of GDDR5 memory is set to run at 1500 MHz through a 384-bit bus. It also features 2048 Stream Processors, 128 TAUs, and 32 ROPs.
Compare those specs to the Radeon R9 290X, which makes use of a 28 nm design. AMD has set the core speed at 800 MHz. The GDDR5 RAM works at a speed of 1250 MHz on this specific model. It features 2816 SPUs as well as 176 TAUs and 64 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7990 will be 80% faster than the Radeon R9 290X overall, due to its higher bandwidth. (explain)
Texel RateThe Radeon HD 7990 should be quite a bit (approximately 73%) faster with regards to anisotropic filtering than the Radeon R9 290X. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the Radeon HD 7990 is superior to the Radeon R9 290X, but it probably won't make a huge difference. (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 data (measured in megabytes per second) that can be moved past the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the video 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 most pixels that the graphics chip can possibly record to the local memory in a 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 filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.