Compare any two graphics cards:
Radeon HD 5770 vs Radeon HD 6850
IntroThe Radeon HD 5770 has a core clock frequency of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also makes use of a 128-bit memory bus, and makes use of a 40 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon HD 6850, which uses a 40 nm design. AMD has set the core speed at 775 MHz. The GDDR5 RAM works at a speed of 1000 MHz on this particular card. It features 960 SPUs as well as 48 Texture Address Units and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6850 will be 67% faster than the Radeon HD 5770 in general, because of its greater bandwidth. (explain)
Texel RateThe Radeon HD 6850 should be just a bit (about 9%) more effective at AF than the Radeon HD 5770. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 6850 is superior to the Radeon HD 5770, and very much so. (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 maximum amount of information (in units of megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory speed. If the card has DDR RAM, 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 AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one 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 number is worked out by multiplying the number of Raster Operations Pipelines 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 - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.