GeForce 8400 GS 512MB vs GeForce 9800 GX2

Intro

Compare those specs to the GeForce 9800 GX2, which comes with a core clock frequency of 600 MHz and a GDDR3 memory speed of 1000 MHz. It also makes use of a 256-bit bus, and uses a 65 nm design. It is comprised of 128 SPUs, 64 Texture Address Units, 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

Theoretically, the GeForce 9800 GX2 should be quite a bit faster than the GeForce 8400 GS 512MB in general. (explain)

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

Texel Rate

The GeForce 9800 GX2 should be much (more or less 1377%) better at AF 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

If running with a high screen resolution is important to you, then the GeForce 9800 GX2 is superior to the GeForce 8400 GS 512MB, and very much so. (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 data (counted in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better 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 can be processed in one second. This figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory in a 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 drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.