Radeon HD 3850 X2 vs Radeon HD 7870

Intro

Compare that to the Radeon HD 7870, which features GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also features 1280 Stream Processors, 80 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 7870 should in theory be quite a bit superior to the Radeon HD 3850 X2 in general. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 47616 (45%)

Texel Rate

The Radeon HD 7870 should be much (more or less 274%) more effective at anisotropic filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 58624 (274%)

Pixel Rate

The Radeon HD 7870 will be quite a bit (more or less 50%) more effective at AA than the Radeon HD 3850 X2, and also able to handle higher screen resolutions better. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 3850 X2		21376 Mpixels/sec
	Difference: 10624 (50%)

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 largest amount of data (measured in megabytes per second) that can be moved over the external memory interface in one 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 must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the video 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 card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.