Compare any two graphics cards:
GeForce 9800 GT 1GB vs GeForce GT 340
IntroThe GeForce 9800 GT 1GB features core speeds of 600 MHz on the GPU, and 900 MHz on the 1024 MB of GDDR3 RAM. It features 112 SPUs as well as 56 Texture Address Units and 16 ROPs.
Compare those specifications to the GeForce GT 340, which comes with core speeds of 550 MHz on the GPU, and 850 MHz on the 512 MB of GDDR5 memory. It features 96 SPUs along with 32 TAUs and 8 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce 9800 GT 1GB is 6% faster than the GeForce GT 340 overall, due to its higher bandwidth. (explain)
Texel RateThe GeForce 9800 GT 1GB will be much (about 91%) better at anisotropic filtering than the GeForce GT 340. (explain)
Pixel RateIf using high levels of AA is important to you, then the GeForce 9800 GT 1GB is a better choice, 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 information (counted in megabytes per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. 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 texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at 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 record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.