Compare any two graphics cards:
Radeon HD 4870 X2 vs Radeon HD 5870
IntroThe Radeon HD 4870 X2 makes use of a 55 nm design. AMD has set the core frequency at 750 MHz. The GDDR5 memory works at a speed of 900 MHz on this particular card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.
Compare that to the Radeon HD 5870, which has a core clock frequency of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also makes use of a 256-bit bus, and makes use of a 40 nm design. It is made up of 1600(320x5) SPUs, 80 TAUs, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 4870 X2 should perform quite a bit faster than the Radeon HD 5870 in general. (explain)
Texel RateThe Radeon HD 5870 should be a small bit (about 13%) more effective at texture filtering than the Radeon HD 4870 X2. (explain)
Pixel RateThe Radeon HD 5870 is a bit (more or less 13%) better at full screen anti-aliasing than the Radeon HD 4870 X2, and also capable of handling higher resolutions while still performing well. (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 max amount of data (counted in megabytes per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If 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 high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.