Compare any two graphics cards:
GeForce GTX 660 vs Radeon HD 7870
IntroThe GeForce GTX 660 has clock speeds of 980 MHz on the GPU, and 1502 MHz on the 2048 MB of GDDR5 RAM. It features 960 SPUs as well as 80 TAUs and 24 Rasterization Operator Units.
Compare that to the Radeon HD 7870, which has a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also is made up of 1280 Stream Processors, 80 Texture Address Units, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7870 will be 7% faster than the GeForce GTX 660 overall, because of its greater data rate. (explain)
Texel RateThe Radeon HD 7870 will be a little bit (about 2%) better at anisotropic filtering than the GeForce GTX 660. (explain)
Pixel RateThe Radeon HD 7870 is a lot (about 36%) more effective at FSAA than the GeForce GTX 660, and capable of handling higher 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.
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: Bandwidth is the largest amount of data (measured in megabytes per second) that can be transported across the external memory interface in one second. It is calculated by multiplying the bus width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total texture units by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant 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 max fill rate.