Radeon HD 3870 X2 512MB vs Radeon HD 4830 512MB

Intro

Compare those specifications to the Radeon HD 4830 512MB, which has core speeds of 575 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 640(128x5) SPUs as well as 32 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 3870 X2 512MB should in theory be much better than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 57600 (100%)

Texel Rate

The Radeon HD 3870 X2 512MB should be much (more or less 43%) better at anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 8000 (43%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 3870 X2 512MB is a better choice, by far. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 17200 (187%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred across the external memory interface within a second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, 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 faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This is calculated by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also 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, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.