GeForce 8400 GS 512MB vs GeForce 8500 GT

Intro

Compare all of that to the GeForce 8500 GT, which makes use of a 80 nm design. nVidia has set the core frequency at 450 MHz. The DDR2 memory runs at a frequency of 400 MHz on this specific model. It features 16 SPUs along with 8 Texture Address Units and 4 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
GeForce 8500 GT		45 Watts
	Difference: 5 Watts (13%)

Memory Bandwidth

Performance-wise, the GeForce 8500 GT should in theory be a lot better than the GeForce 8400 GS 512MB in general. (explain)

GeForce 8500 GT		12800 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 6400 (100%)

Texel Rate

The GeForce 8400 GS 512MB will be quite a bit (more or less 44%) better at anisotropic filtering than the GeForce 8500 GT. (explain)

GeForce 8400 GS 512MB		5200 Mtexels/sec
GeForce 8500 GT		3600 Mtexels/sec
	Difference: 1600 (44%)

Pixel Rate

The GeForce 8400 GS 512MB should be a lot (approximately 44%) more effective at full screen anti-aliasing than the GeForce 8500 GT, and capable of handling higher resolutions without losing too much performance. (explain)

GeForce 8400 GS 512MB		2600 Mpixels/sec
GeForce 8500 GT		1800 Mpixels/sec
	Difference: 800 (44%)

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: Bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred across the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 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 AA, HDR and high resolutions.

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