Compare any two graphics cards:
Radeon HD 3850 1GB vs Radeon HD 4850 X2 1GB
IntroThe Radeon HD 3850 1GB has a clock frequency of 668 MHz and a GDDR3 memory speed of 828 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It features 320(64x5) SPUs, 16 TAUs, and 16 ROPs.
Compare all that to the Radeon HD 4850 X2 1GB, which makes use of a 55 nm design. AMD has set the core frequency at 625 MHz. The GDDR3 memory runs at a speed of 993 MHz on this particular card. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 4850 X2 1GB should in theory perform a lot faster than the Radeon HD 3850 1GB overall. (explain)
Texel RateThe Radeon HD 4850 X2 1GB is much (approximately 368%) faster with regards to AF than the Radeon HD 3850 1GB. (explain)
Pixel RateThe Radeon HD 4850 X2 1GB will be quite a bit (about 87%) better at anti-aliasing than the Radeon HD 3850 1GB, and also will be able to handle higher resolutions more effectively. (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: Memory bandwidth is the largest 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 bus width by the speed of its memory. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core 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 rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.