Compare any two graphics cards:
Radeon HD 6770 1GB vs Radeon R9 M275X
IntroThe Radeon HD 6770 1GB features core speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 800 SPUs as well as 40 Texture Address Units and 16 ROPs.
Compare those specifications to the Radeon R9 M275X, which features GPU core speed of 900 MHz, and 2048 MB of GDDR5 RAM set to run at 1125 MHz through a 128-bit bus. It also features 640 SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon R9 M275X should in theory be just a bit superior to the Radeon HD 6770 1GB overall. (explain)
Texel RateBoth cards have exactly the same texel rate, so theoretically they should perform equally good at at anisotropic filtering. (explain)
Pixel RateBoth cards have exactly the same pixel fill rate, so in theory they should perform equally good at at anti-aliasing, and be capable of handling the same screen resolutions. (explain)
Memory Bandwidth: Bandwidth is the max amount of information (in units of megabytes per second) that can be transported across the external memory interface in one second. It is calculated by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.