GeForce 9400 GT 256MB vs GeForce 9800 GX2

Intro

Compare all of that to the GeForce 9800 GX2, which has a core clock speed of 600 MHz and a GDDR3 memory frequency of 1000 MHz. It also features a 256-bit bus, and uses a 65 nm design. It is comprised of 128 SPUs, 64 TAUs, and 16 Raster Operation Units.

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

Theoretically speaking, the GeForce 9800 GX2 is 900% quicker than the GeForce 9400 GT 256MB in general, due to its greater bandwidth. (explain)

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

Texel Rate

The GeForce 9800 GX2 should be a lot (more or less 1645%) better 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 much (approximately 773%) better at FSAA than the GeForce 9400 GT 256MB, and able to handle higher screen resolutions while still performing well. (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: Bandwidth is the largest amount of information (measured in MB 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 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 in one second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.