Compare any two graphics cards:
Radeon HD 6950 2GB vs Radeon HD 7950 3GB
IntroThe Radeon HD 6950 2GB features clock speeds of 800 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 1408 SPUs as well as 88 Texture Address Units and 32 ROPs.
Compare those specs to the Radeon HD 7950 3GB, which features a core clock frequency of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 384-bit memory bus, and makes use of a 28 nm design. It is comprised of 1792 SPUs, 112 Texture Address Units, and 32 ROPs.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Performance-wise, the Radeon HD 7950 3GB should theoretically be quite a bit better than the Radeon HD 6950 2GB in general. (explain)
Texel RateThe Radeon HD 7950 3GB is much (more or less 27%) faster with regards to anisotropic filtering than the Radeon HD 6950 2GB. (explain)
Pixel RateBoth cards have exactly the same pixel fill rate, so in theory they should perform equally good at at FSAA, and be capable of handling the same resolutions. (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: Memory bandwidth is the max amount of information (measured in megabytes per second) that can be moved past the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock 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 card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to its 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 core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.