Compare any two graphics cards:
GeForce GTX 580 vs Radeon HD 7850
IntroThe GeForce GTX 580 comes with a GPU core clock speed of 772 MHz, and the 1536 MB of GDDR5 memory runs at 1002 MHz through a 384-bit bus. It also is made up of 512 Stream Processors, 64 TAUs, and 48 ROPs.
Compare those specifications to the Radeon HD 7850, which has core clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. It features 1024 SPUs along with 64 Texture Address Units and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 580 should be 25% quicker than the Radeon HD 7850 overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7850 will be a little bit (more or less 11%) more effective at AF than the GeForce GTX 580. (explain)
Pixel RateThe GeForce GTX 580 will be a lot (more or less 35%) better at full screen anti-aliasing than the Radeon HD 7850, and will be able to handle higher resolutions without slowing down too much. (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 over the external memory interface in one second. It is calculated by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.