Radeon HD 5770 vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which has a GPU core clock speed of 830 MHz, and 2048 MB of GDDR5 RAM set to run at 1250 MHz through a 256-bit bus. It also features 1536 Stream Processors, 96 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5770		108 Watts
Radeon HD 6990		375 Watts
	Difference: 267 Watts (247%)

Memory Bandwidth

Theoretically, the Radeon HD 6990 should be much faster than the Radeon HD 5770 overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 5770		76800 MB/sec
	Difference: 243200 (317%)

Texel Rate

The Radeon HD 6990 is a lot (about 369%) faster with regards to AF than the Radeon HD 5770. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 5770		34000 Mtexels/sec
	Difference: 125360 (369%)

Pixel Rate

The Radeon HD 6990 is quite a bit (about 291%) more effective at full screen anti-aliasing than the Radeon HD 5770, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 5770		13600 Mpixels/sec
	Difference: 39520 (291%)

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 largest amount of data (counted in MB per second) that can be transported over the external memory interface in a second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

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