Radeon HD 6990 vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, which comes with a clock speed of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 384-bit memory bus, and makes use of a 28 nm design. It features 1792 SPUs, 112 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7950 3GB		200 Watts
Radeon HD 6990		375 Watts
	Difference: 175 Watts (88%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should theoretically be a lot superior to the Radeon HD 7950 3GB in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 7950 3GB		240000 MB/sec
	Difference: 80000 (33%)

Texel Rate

The Radeon HD 6990 is quite a bit (approximately 78%) better at texture filtering than the Radeon HD 7950 3GB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 7950 3GB		89600 Mtexels/sec
	Difference: 69760 (78%)

Pixel Rate

The Radeon HD 6990 is much (approximately 108%) faster with regards to full screen anti-aliasing than the Radeon HD 7950 3GB, and capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 7950 3GB		25600 Mpixels/sec
	Difference: 27520 (108%)

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 (in units of megabytes per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the interface width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. 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 can be processed in one second. This number is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the video card will be at handling 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 chip can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.