Compare any two graphics cards:
Geforce GTX 690 vs Radeon HD 7970
IntroThe Geforce GTX 690 has clock speeds of 915 MHz on the GPU, and 1502 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs along with 128 TAUs and 32 Rasterization Operator Units.
Compare that to the Radeon HD 7970, which comes with GPU clock speed of 925 MHz, and 3072 MB of GDDR5 memory set to run at 1375 MHz through a 384-bit bus. It also is made up of 2048 Stream Processors, 128 Texture Address Units, and 32 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 Geforce GTX 690 should theoretically be a lot better than the Radeon HD 7970 overall. (explain)
Texel RateThe Geforce GTX 690 is much (approximately 98%) more effective at texture filtering than the Radeon HD 7970. (explain)
Pixel RateIf using high levels of AA is important to you, then the Geforce GTX 690 is the winner, by a large margin. (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 (in units of megabytes per second) that can be transferred over the external memory interface in a second. The number is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.