GeForce 9400 GT 256MB vs GeForce 9800 GX2

Intro

Compare that to the GeForce 9800 GX2, which uses a 65 nm design. nVidia has set the core speed at 600 MHz. The GDDR3 memory runs at a frequency of 1000 MHz on this particular card. It features 128 SPUs as well as 64 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9400 GT 256MB		50 Watts
GeForce 9800 GX2		197 Watts
	Difference: 147 Watts (294%)

Memory Bandwidth

Performance-wise, the GeForce 9800 GX2 should theoretically be much superior to the GeForce 9400 GT 256MB in general. (explain)

GeForce 9800 GX2		128000 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 115200 (900%)

Texel Rate

The GeForce 9800 GX2 is quite a bit (more or less 1645%) more effective at anisotropic filtering than the GeForce 9400 GT 256MB. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 72400 (1645%)

Pixel Rate

The GeForce 9800 GX2 will be a lot (more or less 773%) faster with regards to full screen anti-aliasing than the GeForce 9400 GT 256MB, and should be able to handle higher resolutions better. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 17000 (773%)

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 largest amount of information (in units of megabytes per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster 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 are processed per second. This number is worked out by multiplying the total texture units by the core speed of the chip. The better the texel rate, 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 number of pixels that the graphics chip could possibly record to its local memory in one 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 outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.