Compare any two graphics cards:
Radeon HD 6950 2GB vs Radeon HD 7950 3GB
IntroThe Radeon HD 6950 2GB comes with core 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 has a clock frequency of 800 MHz and a GDDR5 memory speed 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 TAUs, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
In theory, the Radeon HD 7950 3GB should be 50% faster than the Radeon HD 6950 2GB in general, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7950 3GB should be much (more or less 27%) faster with regards to texture filtering than the Radeon HD 6950 2GB. (explain)
Pixel RateBoth cards have the exact same pixel fill rate, so theoretically they should be equally good at at anti-aliasing, 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: Memory bandwidth is the max amount of data (measured in MB per second) that can be transferred past the external memory interface in one second. It is worked out by multiplying the bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video 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 amount of colour ROPs 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 rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.