Radeon HD 6850 vs Radeon HD 6990

Intro

Compare all of that to the Radeon HD 6990, which comes with a core clock frequency of 830 MHz and a GDDR5 memory frequency of 1250 MHz. It also makes use of a 256-bit bus, and uses a 40 nm design. It is comprised of 1536 SPUs, 96 TAUs, and 32 Raster Operation Units.

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

Theoretically speaking, the Radeon HD 6990 is 150% faster than the Radeon HD 6850 overall, because of its higher data rate. (explain)

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

Texel Rate

The Radeon HD 6990 is much (more or less 328%) better at anisotropic filtering than the Radeon HD 6850. (explain)

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

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 6990 is the winner, and very much so. (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 maximum amount of data (measured in megabytes per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it should 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 higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.