Radeon HD 6850 vs Radeon HD 6990

Intro

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

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

Radeon HD 6990		5820 points
Radeon HD 6850		2395 points
	Difference: 3425 (143%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6850		127 Watts
Radeon HD 6990		375 Watts
	Difference: 248 Watts (195%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should in theory be a lot better than the Radeon HD 6850 in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 6850		128000 MB/sec
	Difference: 192000 (150%)

Texel Rate

The Radeon HD 6990 is a lot (about 328%) faster with regards to AF than the Radeon HD 6850. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 6850		37200 Mtexels/sec
	Difference: 122160 (328%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6990 is the winner, by a large margin. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 6850		24800 Mpixels/sec
	Difference: 28320 (114%)

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 max amount of data (in units of MB per second) that can be transported past the external memory interface in one second. It is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 amount of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the video 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 number of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated 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 rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.