Compare any two graphics cards:
Radeon HD 3850 X2 vs Radeon HD 4830 512MB
IntroThe Radeon HD 3850 X2 has a core clock speed 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 is comprised of 320(64x5) SPUs, 16 TAUs, and 16 ROPs.
Compare all that to the Radeon HD 4830 512MB, which makes use of a 55 nm design. AMD has clocked the core frequency at 575 MHz. The GDDR3 memory runs at a speed of 900 MHz on this model. It features 640(128x5) SPUs as well as 32 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
In theory, the Radeon HD 3850 X2 should be a lot faster than the Radeon HD 4830 512MB overall. (explain)
Texel RateThe Radeon HD 3850 X2 is a small bit (approximately 16%) better at texture filtering than the Radeon HD 4830 512MB. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 3850 X2 is a better choice, and very much so. (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 moved past the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the 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 amount of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total number of texture units by the core clock 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 in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.