Compare any two graphics cards:
Radeon HD 6670 (OEM) vs Radeon HD 7770
IntroThe Radeon HD 6670 (OEM) uses a 40 nm design. AMD has set the core frequency at 800 MHz. The GDDR5 RAM runs at a speed of 1000 MHz on this particular model. It features 480 SPUs along with 24 Texture Address Units and 8 Rasterization Operator Units.
Compare all that to the Radeon HD 7770, which has a clock frequency of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit bus, and makes use of a 28 nm design. It features 640 SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 7770 will be 13% faster than the Radeon HD 6670 (OEM) overall, because of its greater bandwidth. (explain)
Texel RateThe Radeon HD 7770 will be a lot (more or less 108%) more effective at anisotropic filtering than the Radeon HD 6670 (OEM). (explain)
Pixel RateThe Radeon HD 7770 will be much (about 150%) faster with regards to full screen anti-aliasing than the Radeon HD 6670 (OEM), and also able to handle higher screen resolutions while still performing well. (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 max amount of data (measured in megabytes per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the video 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 amount of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core 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 also depends 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 maximum fill rate.