Compare any two graphics cards:
Radeon HD 7770 vs Radeon HD 7870
IntroThe Radeon HD 7770 has a GPU core speed of 1000 MHz, and the 1024 MB of GDDR5 memory runs at 1125 MHz through a 128-bit bus. It also features 640 Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.
Compare those specs to the Radeon HD 7870, which makes use of a 28 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 memory runs at a frequency of 1200 MHz on this particular card. It features 1280 SPUs along with 80 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7870 should perform much faster than the Radeon HD 7770 in general. (explain)
Texel RateThe Radeon HD 7870 will be a lot (approximately 100%) faster with regards to texture filtering than the Radeon HD 7770. (explain)
Pixel RateThe Radeon HD 7870 should be a lot (more or less 100%) faster with regards to full screen anti-aliasing than the Radeon HD 7770, and also will be capable of handling higher resolutions better. (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 (counted in megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 are processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka 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, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.