GeForce 9800 GX2 vs Radeon HD 7850

Intro

Compare all of that to the Radeon HD 7850, which comes with core clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1024 SPUs as well as 64 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7850		130 Watts
GeForce 9800 GX2		197 Watts
	Difference: 67 Watts (52%)

Memory Bandwidth

Theoretically, the Radeon HD 7850 should be a bit faster than the GeForce 9800 GX2 in general. (explain)

Radeon HD 7850		153600 MB/sec
GeForce 9800 GX2		128000 MB/sec
	Difference: 25600 (20%)

Texel Rate

The GeForce 9800 GX2 should be much (more or less 40%) faster with regards to texture filtering than the Radeon HD 7850. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 7850		55040 Mtexels/sec
	Difference: 21760 (40%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7850 is the winner, by far. (explain)

Radeon HD 7850		27520 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 8320 (43%)

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 information (in units of megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 once again. If 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, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the 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 most pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines 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 fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.