Compare any two graphics cards:
GeForce GTX 260 Core 216 vs GeForce GTX 465
IntroThe GeForce GTX 260 Core 216 features a GPU core speed of 576 MHz, and the 896 MB of GDDR3 memory runs at 999 MHz through a 448-bit bus. It also is comprised of 216 SPUs, 72 Texture Address Units, and 28 Raster Operation Units.
Compare all that to the GeForce GTX 465, which comes with core clock speeds of 607 MHz on the GPU, and 802 MHz on the 1024 MB of GDDR5 RAM. It features 352 SPUs as well as 44 Texture Address Units and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 260 Core 216 should be 9% quicker than the GeForce GTX 465 overall, because of its higher bandwidth. (explain)
Texel RateThe GeForce GTX 260 Core 216 should be much (about 55%) faster with regards to texture filtering than the GeForce GTX 465. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the GeForce GTX 465 is a better choice, but not by far. (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.
Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of MB per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's 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 texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core speed of the card. 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 also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.