Compare any two graphics cards:
Radeon HD 4850 1GB vs Radeon HD 5870
IntroThe Radeon HD 4850 1GB has a core clock frequency of 625 MHz and a GDDR4 memory speed of 993 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Compare those specs to the Radeon HD 5870, which features a GPU core clock speed of 850 MHz, and 1024 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also is comprised of 1600(320x5) Stream Processors, 80 Texture Address Units, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 5870 should perform quite a bit faster than the Radeon HD 4850 1GB in general. (explain)
Texel RateThe Radeon HD 5870 is a lot (about 172%) more effective at texture filtering than the Radeon HD 4850 1GB. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 5870 is superior to the Radeon HD 4850 1GB, 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: Bandwidth is the max amount of data (measured in megabytes per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.