Compare any two graphics cards:
Radeon HD 6950 2GB vs Radeon HD 7950 3GB
IntroThe Radeon HD 6950 2GB features a clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 256-bit memory bus, and uses a 40 nm design. It features 1408 SPUs, 88 TAUs, and 32 ROPs.
Compare those specifications to the Radeon HD 7950 3GB, which has core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 3072 MB of GDDR5 RAM. It features 1792 SPUs as well as 112 Texture Address Units and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Theoretically, the Radeon HD 7950 3GB should perform a lot faster than the Radeon HD 6950 2GB in general. (explain)
Texel RateThe Radeon HD 7950 3GB will be a lot (approximately 27%) better at texture filtering than the Radeon HD 6950 2GB. (explain)
Pixel RateBoth cards have the exact same pixel rate, so theoretically they should be equally good at at FSAA, and be able to handle 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 largest amount of data (in units of MB per second) that can be transferred across the external memory interface within a second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. 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 number of texture units of the card by the core 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 per second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card could 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 Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.