GeForce 8400 GS 512MB vs GeForce 9800 GTX

Intro

Compare that to the GeForce 9800 GTX, which has core speeds of 675 MHz on the GPU, and 1100 MHz on the 512 MB of GDDR3 memory. It features 128 SPUs as well as 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 GTX		140 Watts
	Difference: 100 Watts (250%)

Memory Bandwidth

In theory, the GeForce 9800 GTX should be 1000% quicker than the GeForce 8400 GS 512MB in general, due to its greater data rate. (explain)

GeForce 9800 GTX		70400 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 64000 (1000%)

Texel Rate

The GeForce 9800 GTX should be much (about 731%) better at texture filtering than the GeForce 8400 GS 512MB. (explain)

GeForce 9800 GTX		43200 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 38000 (731%)

Pixel Rate

The GeForce 9800 GTX is a lot (more or less 315%) better at anti-aliasing than the GeForce 8400 GS 512MB, and will be capable of handling higher resolutions more effectively. (explain)

GeForce 9800 GTX		10800 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 8200 (315%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (in units of MB per second) that can be transferred past the external memory interface in a second. It is calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum 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 speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate 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 fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.