Radeon HD 3870 1GB vs Radeon HD 6870

Intro

Compare all of that to the Radeon HD 6870, which features a clock frequency of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also uses a 256-bit bus, and uses a 40 nm design. It is comprised of 1120 SPUs, 56 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
Radeon HD 6870		151 Watts
	Difference: 45 Watts (42%)

Memory Bandwidth

The Radeon HD 6870 should theoretically be a lot faster than the Radeon HD 3870 1GB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 62400 (87%)

Texel Rate

The Radeon HD 6870 should be quite a bit (about 306%) faster with regards to AF than the Radeon HD 3870 1GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 38000 (306%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6870 is superior to the Radeon HD 3870 1GB, by a large margin. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 16400 (132%)

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 (measured in megabytes per second) that can be transported past the external memory interface in a second. The number is worked out by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the card will be at handling 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 can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines 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 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.