GeForce 8400 GS 512MB vs Radeon HD 6870

Intro

Compare all that to the Radeon HD 6870, which comes with clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 1120 SPUs as well as 56 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
Radeon HD 6870		151 Watts
	Difference: 111 Watts (278%)

Memory Bandwidth

The Radeon HD 6870, in theory, should perform much faster than the GeForce 8400 GS 512MB in general. (explain)

Radeon HD 6870		134400 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 128000 (2000%)

Texel Rate

The Radeon HD 6870 is a lot (approximately 869%) more effective at anisotropic filtering than the GeForce 8400 GS 512MB. (explain)

Radeon HD 6870		50400 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 45200 (869%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 6870 is superior to the GeForce 8400 GS 512MB, by far. (explain)

Radeon HD 6870		28800 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 26200 (1008%)

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 (counted in megabytes per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.