Compare any two graphics cards:
GeForce GTX 650 vs GeForce GTX 660
IntroThe GeForce GTX 650 features clock speeds of 1058 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 384 SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.
Compare those specifications to the GeForce GTX 660, which has a GPU core clock speed of 980 MHz, and 2048 MB of GDDR5 RAM set to run at 1502 MHz through a 192-bit bus. It also is made up of 960 SPUs, 80 Texture Address Units, and 24 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 660 should be 80% quicker than the GeForce GTX 650 overall, because of its higher bandwidth. (explain)
Texel RateThe GeForce GTX 660 should be quite a bit (about 132%) better at texture filtering than the GeForce GTX 650. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce GTX 660 is superior to the GeForce GTX 650, 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.
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 transferred over the external memory interface within a second. It is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's 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 can be processed per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the 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 record to the local memory in a second - measured in millions of pixels per second. The figure 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 rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.