Radeon HD 3870 1GB vs Radeon HD 3870 512MB

Intro

Compare those specifications to the Radeon HD 3870 512MB, which comes with 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 TAUs and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

Performance-wise, the Radeon HD 3870 1GB should theoretically be much better 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 the exact same texel rate, so theoretically they should perform equally good at at AF. (explain)

Pixel Rate

Both cards have the exact same pixel rate, so theoretically they should be equally good at at AA, 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 maximum amount of data (counted in MB per second) that can be moved across the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.