Radeon HD 3870 512MB vs Radeon HD 7970

Intro

Compare that to the Radeon HD 7970, which comes with GPU clock speed of 925 MHz, and 3072 MB of GDDR5 memory running at 1375 MHz through a 384-bit bus. It also is made up of 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 7970		250 Watts
	Difference: 144 Watts (136%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7970 is 358% quicker than the Radeon HD 3870 512MB in general, because of its greater data rate. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 206400 (358%)

Texel Rate

The Radeon HD 7970 is quite a bit (approximately 855%) better at AF than the Radeon HD 3870 512MB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 106000 (855%)

Pixel Rate

The Radeon HD 7970 should be quite a bit (approximately 139%) faster with regards to FSAA than the Radeon HD 3870 512MB, and also should be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 17200 (139%)

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 max amount of information (counted in megabytes per second) that can be transported across the external memory interface in one second. The number is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 are processed per second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.