Compare any two graphics cards:
Radeon HD 4850 X2 1GB vs Radeon HD 4870 X2
IntroThe Radeon HD 4850 X2 1GB uses a 55 nm design. AMD has set the core frequency at 625 MHz. The GDDR3 memory works at a speed of 993 MHz on this particular model. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.
Compare those specs to the Radeon HD 4870 X2, which uses a 55 nm design. AMD has set the core frequency at 750 MHz. The GDDR5 RAM works at a speed of 900 MHz on this model. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 4870 X2 should theoretically be a lot superior to the Radeon HD 4850 X2 1GB overall. (explain)
Texel RateThe Radeon HD 4870 X2 is a bit (about 20%) faster with regards to AF than the Radeon HD 4850 X2 1GB. (explain)
Pixel RateThe Radeon HD 4870 X2 is a bit (more or less 20%) faster with regards to anti-aliasing than the Radeon HD 4850 X2 1GB, and should be able to handle higher 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: Memory bandwidth is the max amount of information (counted in MB per second) that can be transported across the external memory interface in one second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This 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 processed per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.