Compare any two graphics cards:
Radeon HD 7990 vs Radeon R9 290X
IntroThe Radeon HD 7990 uses a 28 nm design. AMD has set the core frequency at 950 MHz. The GDDR5 memory is set to run at a frequency of 1500 MHz on this specific model. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.
Compare those specifications to the Radeon R9 290X, which comes with a GPU core clock speed of 800 MHz, and 4096 MB of GDDR5 RAM set to run at 1250 MHz through a 512-bit bus. It also is comprised of 2816 SPUs, 176 Texture Address Units, and 64 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the Radeon HD 7990 should in theory be quite a bit better than the Radeon R9 290X overall. (explain)
Texel RateThe Radeon HD 7990 is quite a bit (approximately 73%) more effective at texture filtering than the Radeon R9 290X. (explain)
Pixel RateThe Radeon HD 7990 should be a bit (about 19%) better at FSAA than the Radeon R9 290X, and will be able to handle higher screen resolutions more effectively. (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 largest amount of information (counted in MB per second) that can be moved across the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.