GeForce 9800 GX2 vs Radeon HD 6850

Intro

Compare all that to the Radeon HD 6850, which features a core clock speed of 775 MHz and a GDDR5 memory speed of 1000 MHz. It also makes use of a 256-bit bus, and makes use of a 40 nm design. It is comprised of 960 SPUs, 48 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6850		127 Watts
GeForce 9800 GX2		197 Watts
	Difference: 70 Watts (55%)

Memory Bandwidth

Both cards have exactly the same bandwidth, so theoretically they should have identical performance. (explain)

Texel Rate

The GeForce 9800 GX2 should be a lot (about 106%) more effective at AF than the Radeon HD 6850. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 6850		37200 Mtexels/sec
	Difference: 39600 (106%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 6850 is the winner, and very much so. (explain)

Radeon HD 6850		24800 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 5600 (29%)

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 data (counted in megabytes per second) that can be transported past the external memory interface in a second. It is calculated by multiplying the bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher 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 amount of pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.