GeForce 8400 GS 512MB vs GeForce GTS 450 1GB

Intro

Compare those specifications to the GeForce GTS 450 1GB, which comes with a core clock speed of 783 MHz and a GDDR5 memory frequency of 902 MHz. It also makes use of a 128-bit memory bus, and uses a 40 nm design. It is comprised of 192 SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
GeForce GTS 450 1GB		106 Watts
	Difference: 66 Watts (165%)

Memory Bandwidth

In theory, the GeForce GTS 450 1GB is 802% quicker than the GeForce 8400 GS 512MB overall, because of its higher data rate. (explain)

GeForce GTS 450 1GB		57728 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 51328 (802%)

Texel Rate

The GeForce GTS 450 1GB is quite a bit (more or less 382%) more effective at anisotropic filtering than the GeForce 8400 GS 512MB. (explain)

GeForce GTS 450 1GB		25056 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 19856 (382%)

Pixel Rate

The GeForce GTS 450 1GB will be a lot (more or less 382%) better at full screen anti-aliasing than the GeForce 8400 GS 512MB, and also capable of handling higher screen resolutions without losing too much performance. (explain)

GeForce GTS 450 1GB		12528 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 9928 (382%)

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 largest amount of information (in units of MB per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.