Compare any two graphics cards:
Radeon HD 7990 vs Radeon R9 290X
IntroThe Radeon HD 7990 has a core clock frequency of 950 MHz and a GDDR5 memory frequency of 1500 MHz. It also makes use of a 384-bit memory bus, and makes use of a 28 nm design. It features 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.
Compare those specs to the Radeon R9 290X, which comes with core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 memory. It features 2816 SPUs as well as 176 Texture Address Units and 64 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 7990 should perform much faster than the Radeon R9 290X overall. (explain)
Texel RateThe Radeon HD 7990 will be a lot (more or less 73%) better at texture filtering than the Radeon R9 290X. (explain)
Pixel RateIf using high levels of AA is important to you, then the Radeon HD 7990 is a better choice, 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: Memory bandwidth is the largest amount of data (counted in MB per second) that can be transported across the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 number of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling 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 video card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.