Compare any two graphics cards:
Radeon HD 7990 vs Radeon R9 290X
IntroThe Radeon HD 7990 features clock speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs as well as 128 Texture Address Units and 32 ROPs.
Compare all of that to the Radeon R9 290X, which features GPU clock speed of 800 MHz, and 4096 MB of GDDR5 RAM running at 1250 MHz through a 512-bit bus. It also is made up of 2816 Stream Processors, 176 TAUs, and 64 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7990 should perform quite a bit faster than the Radeon R9 290X in general. (explain)
Texel RateThe Radeon HD 7990 is quite a bit (more or less 73%) more effective at anisotropic filtering than the Radeon R9 290X. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 7990 is the winner, not by a very large margin though. (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 (measured in megabytes per second) that can be transferred past the external memory interface within a second. The number is worked out by multiplying the interface width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.