Compare any two graphics cards:
Radeon HD 6870 vs Radeon HD 7850
IntroThe Radeon HD 6870 comes with a GPU clock speed of 900 MHz, and the 1024 MB of GDDR5 memory is set to run at 1050 MHz through a 256-bit bus. It also is made up of 1120 SPUs, 56 Texture Address Units, and 32 ROPs.
Compare all that to the Radeon HD 7850, which has GPU core speed of 860 MHz, and 2048 MB of GDDR5 RAM running at 1200 MHz through a 256-bit bus. It also features 1024 Stream Processors, 64 TAUs, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the Radeon HD 7850 should in theory be a small bit better than the Radeon HD 6870 overall. (explain)
Texel RateThe Radeon HD 7850 will be a small bit (approximately 9%) more effective at texture filtering than the Radeon HD 6870. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the Radeon HD 6870 is superior to the Radeon HD 7850, though not by far. (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 information (measured in MB per second) that can be transferred across the external memory interface within a second. It is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 amount of texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.