Compare any two graphics cards:
Radeon HD 5870 vs Radeon HD 7850
IntroThe Radeon HD 5870 comes with a clock speed of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also makes use of a 256-bit memory bus, and uses a 40 nm design. It is comprised of 1600(320x5) SPUs, 80 TAUs, and 32 ROPs.
Compare all that to the Radeon HD 7850, which comes with GPU clock speed of 860 MHz, and 2048 MB of GDDR5 RAM running at 1200 MHz through a 256-bit bus. It also features 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have the exact same memory bandwidth, so theoretically they should perform exactly the same. (explain)
Texel RateThe Radeon HD 5870 will be a lot (more or less 24%) better at texture filtering than the Radeon HD 7850. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 7850 is superior to the Radeon HD 5870, but it probably won't make a huge difference. (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 (counted in MB per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 number of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.