Compare any two graphics cards:
Radeon HD 7990 vs Radeon R9 290X
IntroThe Radeon HD 7990 makes use of a 28 nm design. AMD has clocked the core frequency at 950 MHz. The GDDR5 RAM runs at a frequency of 1500 MHz on this card. It features 2048 SPUs as well as 128 TAUs and 32 Rasterization Operator Units.
Compare all that to the Radeon R9 290X, which has core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 RAM. It features 2816 SPUs along with 176 TAUs and 64 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 7990 is 80% faster than the Radeon R9 290X in general, due to its greater data rate. (explain)
Texel RateThe Radeon HD 7990 should be much (more or less 73%) faster with regards to anisotropic filtering than the Radeon R9 290X. (explain)
Pixel RateThe Radeon HD 7990 should be a bit (more or less 19%) more effective at AA than the Radeon R9 290X, and also should be capable of handling higher resolutions without losing too much performance. (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 maximum amount of data (counted in megabytes per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the 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 maximum number of pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.