Radeon HD 3870 1GB vs Radeon HD 3870 512MB

Intro

Compare those specifications to the Radeon HD 3870 512MB, which has core clock speeds of 775 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 1GB should perform much faster than the Radeon HD 3870 512MB in general. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

Both cards have exactly the same texel fill rate, so in theory they should perform equally good at at AF. (explain)

Pixel Rate

Both cards have exactly the same pixel rate, so in theory they should be equally good at at FSAA, and be capable of handling the same screen resolutions. (explain)

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 MB per second) that can be transferred past the external memory interface in a second. The number is calculated by multiplying the interface width by its memory clock speed. In the case of DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 amount of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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