GeForce 9400 GT 256MB vs Geforce GTX 680

Intro

Compare that to the Geforce GTX 680, which features a core clock frequency of 1006 MHz and a GDDR5 memory frequency of 1502 MHz. It also makes use of a 256-bit bus, and uses a 28 nm design. It features 1536 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9400 GT 256MB		50 Watts
Geforce GTX 680		195 Watts
	Difference: 145 Watts (290%)

Memory Bandwidth

Theoretically speaking, the Geforce GTX 680 is 1402% quicker than the GeForce 9400 GT 256MB in general, because of its higher bandwidth. (explain)

Geforce GTX 680		192256 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 179456 (1402%)

Texel Rate

The Geforce GTX 680 should be much (about 2827%) better at AF than the GeForce 9400 GT 256MB. (explain)

Geforce GTX 680		128768 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 124368 (2827%)

Pixel Rate

The Geforce GTX 680 is a lot (about 1363%) better at AA than the GeForce 9400 GT 256MB, and also capable of handling higher screen resolutions without slowing down too much. (explain)

Geforce GTX 680		32192 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 29992 (1363%)

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: Memory bandwidth is the max amount of data (in units of MB per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. 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 can be applied in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.