Compare any two graphics cards:
Radeon HD 6950 2GB vs Radeon HD 7950 3GB
IntroThe Radeon HD 6950 2GB comes with core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1408 SPUs along with 88 Texture Address Units and 32 ROPs.
Compare those specifications to the Radeon HD 7950 3GB, which comes with clock speeds of 800 MHz on the GPU, and 1250 MHz on the 3072 MB of GDDR5 memory. It features 1792 SPUs as well as 112 TAUs and 32 ROPs.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Theoretically, the Radeon HD 7950 3GB should perform much faster than the Radeon HD 6950 2GB in general. (explain)
Texel RateThe Radeon HD 7950 3GB will be much (approximately 27%) more effective at texture filtering than the Radeon HD 6950 2GB. (explain)
Pixel RateBoth cards have exactly the same pixel rate, so in theory they should perform equally good at at AA, and be able to handle the same screen 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: Bandwidth is the max amount of information (in units of MB per second) that can be moved across the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better 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 are processed in one second. This number is worked out by multiplying the total texture units of the card by the core 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 per second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.