Compare any two graphics cards:
Radeon HD 7850 vs Radeon HD 7870
IntroThe Radeon HD 7850 features a clock speed of 860 MHz and a GDDR5 memory frequency of 1200 MHz. It also makes use of a 256-bit memory bus, and uses a 28 nm design. It is comprised of 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.
Compare that to the Radeon HD 7870, which uses a 28 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 memory runs at a speed of 1200 MHz on this particular model. It features 1280 SPUs as well as 80 TAUs 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 7870 is a lot (approximately 45%) better at AF than the Radeon HD 7850. (explain)
Pixel RateIf using a high screen resolution is important to you, then the Radeon HD 7870 is a better choice, but only just. (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 data (counted in megabytes per second) that can be transported across the external memory interface within a second. It's worked out by multiplying the interface width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This figure is calculated by multiplying the total texture units by the core speed of the chip. The higher 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 a second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the card's clock speed. 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 output rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.