Compare any two graphics cards:
Radeon HD 4790 vs Radeon HD 4850 X2 1GB
IntroThe Radeon HD 4790 comes with a GPU clock speed of 600 MHz, and the 512 MB of GDDR5 memory runs at 800 MHz through a 256-bit bus. It also is made up of 640(128x5) Stream Processors, 32 TAUs, and 16 Raster Operation Units.
Compare those specifications to the Radeon HD 4850 X2 1GB, which features core clock speeds of 625 MHz on the GPU, and 993 MHz on the 1024 MB of GDDR3 RAM. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
The Radeon HD 4850 X2 1GB, in theory, should perform quite a bit faster than the Radeon HD 4790 in general. (explain)
Texel RateThe Radeon HD 4850 X2 1GB is quite a bit (about 160%) better at AF than the Radeon HD 4790. (explain)
Pixel RateThe Radeon HD 4850 X2 1GB is much (about 108%) better at AA than the Radeon HD 4790, and should be capable of handling higher screen resolutions better. (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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
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 information (in units of MB per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.