GeForce 8400 GS 512MB vs Geforce GTX 680

Intro

Compare that to the Geforce GTX 680, which features GPU core speed of 1006 MHz, and 2048 MB of GDDR5 RAM set to run at 1502 MHz through a 256-bit bus. It also is made up of 1536 SPUs, 128 TAUs, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
Geforce GTX 680		195 Watts
	Difference: 155 Watts (388%)

Memory Bandwidth

Theoretically, the Geforce GTX 680 should perform a lot faster than the GeForce 8400 GS 512MB overall. (explain)

Geforce GTX 680		192256 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 185856 (2904%)

Texel Rate

The Geforce GTX 680 should be quite a bit (approximately 2376%) more effective at anisotropic filtering than the GeForce 8400 GS 512MB. (explain)

Geforce GTX 680		128768 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 123568 (2376%)

Pixel Rate

The Geforce GTX 680 will be much (approximately 1138%) better at AA than the GeForce 8400 GS 512MB, and will be able to handle higher resolutions without slowing down too much. (explain)

Geforce GTX 680		32192 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 29592 (1138%)

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 maximum amount of information (counted in MB per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 maximum amount of pixels the graphics card could possibly write to the local memory in a 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 clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.