Compare any two graphics cards:
Radeon HD 5830 vs Radeon HD 6850
IntroThe Radeon HD 5830 has a GPU clock speed of 800 MHz, and the 1024 MB of GDDR5 RAM is set to run at 1000 MHz through a 256-bit bus. It also is made up of 1120(224x5) Stream Processors, 56 TAUs, and 16 Raster Operation Units.
Compare those specifications to the Radeon HD 6850, which features core speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 960 SPUs along with 48 Texture Address Units and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have exactly the same bandwidth, so in theory they should have the same performance. (explain)
Texel RateThe Radeon HD 5830 will be just a bit (about 20%) better at anisotropic filtering than the Radeon HD 6850. (explain)
Pixel RateThe Radeon HD 6850 will be a lot (about 94%) better at anti-aliasing than the Radeon HD 5830, and should be capable of handling higher screen resolutions better. (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 (counted in MB per second) that can be transferred across the external memory interface in a second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once 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, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.