Compare any two graphics cards:
Radeon HD 4650 512MB vs Radeon HD 7750
IntroThe Radeon HD 4650 512MB has core speeds of 600 MHz on the GPU, and 500 MHz on the 512 MB of DDR2 RAM. It features 320(64x5) SPUs along with 32 Texture Address Units and 8 Rasterization Operator Units.
Compare those specs to the Radeon HD 7750, which comes with a GPU core clock speed of 800 MHz, and 1024 MB of GDDR5 memory set to run at 1125 MHz through a 128-bit bus. It also features 512 Stream Processors, 32 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
The Radeon HD 7750 should theoretically perform much faster than the Radeon HD 4650 512MB in general. (explain)
Texel RateThe Radeon HD 7750 will be a lot (more or less 33%) more effective at anisotropic filtering than the Radeon HD 4650 512MB. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 7750 is the winner, 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: Memory bandwidth is the max amount of data (measured in MB per second) that can be moved across the external memory interface in a second. It is calculated by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 amount of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the card's 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 fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.