Compare any two graphics cards:
Radeon HD 4850 1GB vs Radeon HD 7770
IntroThe Radeon HD 4850 1GB has a core clock frequency of 625 MHz and a GDDR4 memory speed of 993 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Compare all of that to the Radeon HD 7770, which has a core clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit memory bus, and uses a 28 nm design. It is comprised of 640 SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 7770 should perform a bit faster than the Radeon HD 4850 1GB in general. (explain)
Texel RateThe Radeon HD 7770 is a lot (more or less 60%) more effective at anisotropic filtering than the Radeon HD 4850 1GB. (explain)
Pixel RateIf using high levels of AA is important to you, then the Radeon HD 7770 is the winner, and very much so. (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 maximum amount of data (measured in MB per second) that can be transferred over the external memory interface in 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 DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.