Radeon HD 3690/3830 vs Radeon HD 6990

Intro

Compare all of that to the Radeon HD 6990, which comes with clock speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs as well as 96 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3690/3830		75 Watts
Radeon HD 6990		375 Watts
	Difference: 300 Watts (400%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6990 should be quite a bit faster than the Radeon HD 3690/3830 overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 3690/3830		26496 MB/sec
	Difference: 293504 (1108%)

Texel Rate

The Radeon HD 6990 will be a lot (approximately 1391%) better at texture filtering than the Radeon HD 3690/3830. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 3690/3830		10688 Mtexels/sec
	Difference: 148672 (1391%)

Pixel Rate

The Radeon HD 6990 will be a lot (about 397%) more effective at FSAA than the Radeon HD 3690/3830, and should be capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 3690/3830		10688 Mpixels/sec
	Difference: 42432 (397%)

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 maximum amount of information (in units of MB per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the graphics 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 amount of pixels that the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.