Compare any two graphics cards:
Radeon HD 5830 vs Radeon HD 6850
IntroThe Radeon HD 5830 comes with a core clock speed of 800 MHz and a GDDR5 memory speed of 1000 MHz. It also makes use of a 256-bit bus, and makes use of a 40 nm design. It is made up of 1120(224x5) SPUs, 56 TAUs, and 16 ROPs.
Compare those specs to the Radeon HD 6850, which comes with core clock speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 960 SPUs as well as 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 theoretically they should have identical performance. (explain)
Texel RateThe Radeon HD 5830 should be a bit (more or less 20%) faster with regards to texture filtering than the Radeon HD 6850. (explain)
Pixel RateThe Radeon HD 6850 will be a lot (more or less 94%) better at FSAA than the Radeon HD 5830, and also should be able to handle higher resolutions while still performing well. (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 data (measured in megabytes per second) that can be moved over the external memory interface in a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the clock 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 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.