Radeon HD 3850 X2 vs Radeon HD 4870 512MB

Intro

Compare those specs to the Radeon HD 4870 512MB, which features core clock speeds of 750 MHz on the GPU, and 900 MHz on the 512 MB of GDDR5 RAM. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 512MB will be 9% quicker than the Radeon HD 3850 X2 in general, because of its higher data rate. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 9216 (9%)

Texel Rate

The Radeon HD 4870 512MB is quite a bit (approximately 40%) better at AF than the Radeon HD 3850 X2. (explain)

Radeon HD 4870 512MB		30000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 8624 (40%)

Pixel Rate

The Radeon HD 3850 X2 should be much (approximately 78%) better at anti-aliasing than the Radeon HD 4870 512MB, and will be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 9376 (78%)

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 max amount of data (counted in MB per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.