GeForce 8400 GS 512MB vs GeForce 9800 GX2

Intro

Compare all that to the GeForce 9800 GX2, which has a core clock speed of 600 MHz and a GDDR3 memory speed of 1000 MHz. It also uses a 256-bit memory bus, and makes use of a 65 nm design. It is made up of 128 SPUs, 64 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
GeForce 9800 GX2		197 Watts
	Difference: 157 Watts (393%)

Memory Bandwidth

In theory, the GeForce 9800 GX2 will be 1900% quicker than the GeForce 8400 GS 512MB in general, because of its higher bandwidth. (explain)

GeForce 9800 GX2		128000 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 121600 (1900%)

Texel Rate

The GeForce 9800 GX2 is much (more or less 1377%) more effective at anisotropic filtering than the GeForce 8400 GS 512MB. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 71600 (1377%)

Pixel Rate

The GeForce 9800 GX2 should be much (more or less 638%) better at FSAA than the GeForce 8400 GS 512MB, and also should be able to handle higher screen resolutions without slowing down too much. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 16600 (638%)

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 information (in units of megabytes per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

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