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 speed at 750 MHz. The GDDR5 RAM runs at a frequency of 900 MHz on this specific card. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.
Compare all that to the Radeon HD 5870, which has GPU clock speed of 850 MHz, and 1024 MB of GDDR5 memory running at 1200 MHz through a 256-bit bus. It also is comprised of 1600(320x5) Stream Processors, 80 Texture Address Units, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 4870 X2, in theory, should perform quite a bit faster than the Radeon HD 5870 in general. (explain)
Texel RateThe Radeon HD 5870 will be just a bit (about 13%) faster with regards to texture filtering than the Radeon HD 4870 X2. (explain)
Pixel RateThe Radeon HD 5870 is a little bit (about 13%) better at full screen anti-aliasing than the Radeon HD 4870 X2, and also will be capable of handling higher resolutions without losing too much performance. (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 (counted in MB per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the card's bus width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core clock 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 applied in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka 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 - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.