Radeon HD 3850 X2 vs Radeon HD 4870 X2

Intro

Compare those specs to the Radeon HD 4870 X2, which has a core clock frequency of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4870 X2 should theoretically perform much faster than the Radeon HD 3850 X2 overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 124416 (117%)

Texel Rate

The Radeon HD 4870 X2 should be quite a bit (about 181%) more effective at AF than the Radeon HD 3850 X2. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 38624 (181%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4870 X2 is a better choice, though only just barely. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 3850 X2		21376 Mpixels/sec
	Difference: 2624 (12%)

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: Bandwidth is the max amount of information (counted in megabytes per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.