Compare any two graphics cards:
Radeon HD 6950 2GB vs Radeon HD 7950 3GB
IntroThe Radeon HD 6950 2GB comes with a GPU core speed of 800 MHz, and the 2048 MB of GDDR5 RAM is set to run at 1250 MHz through a 256-bit bus. It also is made up of 1408 SPUs, 88 TAUs, and 32 ROPs.
Compare all that to the Radeon HD 7950 3GB, which features a clock frequency of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also features a 384-bit memory bus, and uses a 28 nm design. It is comprised of 1792 SPUs, 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.
Performance-wise, the Radeon HD 7950 3GB should in theory be much better than the Radeon HD 6950 2GB in general. (explain)
Texel RateThe Radeon HD 7950 3GB should be much (approximately 27%) more effective at 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 anti-aliasing, 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 maximum amount of information (in units of megabytes per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the video 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 write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to 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 potential to reach the max fill rate.