Compare any two graphics cards:
Radeon HD 5870 vs Radeon HD 7770
IntroThe Radeon HD 5870 has core clock speeds of 850 MHz on the GPU, and 1200 MHz on the 1024 MB of GDDR5 memory. It features 1600(320x5) SPUs along with 80 Texture Address Units and 32 ROPs.
Compare all of that to the Radeon HD 7770, which has a core clock frequency of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit memory bus, and uses a 28 nm design. It is comprised of 640 SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 5870 should be 113% faster than the Radeon HD 7770 overall, because of its greater data rate. (explain)
Texel RateThe Radeon HD 5870 is much (about 70%) faster with regards to AF than the Radeon HD 7770. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 5870 is superior to the Radeon HD 7770, by a large margin. (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 largest amount of information (in units of MB per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. 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 high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure 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 graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.