Compare any two graphics cards:
Radeon HD 7770 vs Radeon R7 250
IntroThe Radeon HD 7770 comes with a GPU clock speed of 1000 MHz, and the 1024 MB of GDDR5 memory is set to run at 1125 MHz through a 128-bit bus. It also is comprised of 640 SPUs, 40 Texture Address Units, and 16 ROPs.
Compare those specs to the Radeon R7 250, which comes with a clock speed of 1000 MHz and a GDDR5 memory speed of 1150 MHz. It also features a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 384 SPUs, 24 Texture Address Units, and 8 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon R7 250 should be a little bit faster than the Radeon HD 7770 overall. (explain)
Texel RateThe Radeon HD 7770 is a lot (about 67%) more effective at AF than the Radeon R7 250. (explain)
Pixel RateThe Radeon HD 7770 will be much (more or less 100%) faster with regards to FSAA than the Radeon R7 250, and able to handle higher screen 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.
Radeon HD 7770
Radeon R7 250
Memory Bandwidth: Bandwidth is the largest amount of data (in units of MB per second) that can be moved past the external memory interface within a second. The number is calculated by multiplying the bus width by its memory clock speed. If it uses DDR RAM, the result should 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 AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per 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 higher the texel rate, the better the 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 the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.
Radeon HD 7770
Radeon R7 250