Radeon HD 3850 X2 vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which features a clock frequency of 830 MHz and a GDDR5 memory frequency of 1250 MHz. It also makes use of a 256-bit memory bus, and makes use of a 40 nm design. It features 1536 SPUs, 96 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 6990 should theoretically be quite a bit superior to the Radeon HD 3850 X2 in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 214016 (202%)

Texel Rate

The Radeon HD 6990 is a lot (approximately 646%) more effective at texture filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 137984 (646%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6990 is a better choice, by far. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 3850 X2		21376 Mpixels/sec
	Difference: 31744 (149%)

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 information (counted in MB per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's 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 amount of texture map elements (texels) that are processed per second. This number is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. 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 max fill rate.