Compare any two graphics cards:
GeForce 9500 GT DDR2 vs GeForce GT 220 GDDR3
IntroThe GeForce 9500 GT DDR2 has a core clock frequency of 550 MHz and a DDR2 memory frequency of 500 MHz. It also makes use of a 128-bit bus, and makes use of a 65 nm design. It is comprised of 32 SPUs, 16 Texture Address Units, and 8 Raster Operation Units.
Compare those specs to the GeForce GT 220 GDDR3, which comes with core clock speeds of 625 MHz on the GPU, and 1012 MHz on the 512 MB of GDDR3 RAM. It features 48 SPUs along with 16 TAUs and 8 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GT 220 GDDR3 should perform a lot faster than the GeForce 9500 GT DDR2 in general. (explain)
Texel RateThe GeForce GT 220 GDDR3 should be a small bit (approximately 14%) better at AF than the GeForce 9500 GT DDR2. (explain)
Pixel RateThe GeForce GT 220 GDDR3 should be a small bit (approximately 14%) better at anti-aliasing than the GeForce 9500 GT DDR2, and also should be able to handle higher screen resolutions without losing too much performance. (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: Bandwidth is the max amount of information (in units of megabytes per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. 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 texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics 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 number of ROPs by the the card's 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 also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.