Radeon HD 3870 512MB vs Radeon HD 6990

Intro

Compare those specifications to the Radeon HD 6990, which uses a 40 nm design. AMD has clocked the core frequency at 830 MHz. The GDDR5 memory runs at a frequency of 1250 MHz on this particular card. It features 1536 SPUs along with 96 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 6990		375 Watts
	Difference: 269 Watts (254%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should in theory be quite a bit better than the Radeon HD 3870 512MB overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 262400 (456%)

Texel Rate

The Radeon HD 6990 will be quite a bit (more or less 1185%) better at texture filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 146960 (1185%)

Pixel Rate

The Radeon HD 6990 will be much (about 328%) better at FSAA than the Radeon HD 3870 512MB, and also able to handle higher screen resolutions better. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 40720 (328%)

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 (measured in MB per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the video 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 number of pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core 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 is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.