Compare any two graphics cards:
Radeon HD 4850 512MB vs Radeon HD 7850
IntroThe Radeon HD 4850 512MB has a GPU clock speed of 625 MHz, and the 512 MB of GDDR3 memory is set to run at 993 MHz through a 256-bit bus. It also features 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Compare all of that to the Radeon HD 7850, which comes with core speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1024 SPUs as well as 64 Texture Address Units and 32 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 7850 should in theory be a lot faster than the Radeon HD 4850 512MB in general. (explain)
Texel RateThe Radeon HD 7850 will be quite a bit (about 120%) faster with regards to AF than the Radeon HD 4850 512MB. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 7850 is a better choice, by far. (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 maximum amount of data (counted in megabytes per second) that can be moved past the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. 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 amount of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher 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 maximum number of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's 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 also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.