Radeon HD 3870 512MB vs Radeon HD 7850

Intro

Compare all that to the Radeon HD 7850, which features GPU clock speed of 860 MHz, and 2048 MB of GDDR5 RAM running at 1200 MHz through a 256-bit bus. It also features 1024 SPUs, 64 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 7850		130 Watts
	Difference: 24 Watts (23%)

Memory Bandwidth

In theory, the Radeon HD 7850 is 167% faster than the Radeon HD 3870 512MB in general, due to its higher bandwidth. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 96000 (167%)

Texel Rate

The Radeon HD 7850 is much (more or less 344%) better at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 42640 (344%)

Pixel Rate

The Radeon HD 7850 will be much (about 122%) better at full screen anti-aliasing than the Radeon HD 3870 512MB, and also will be able to handle higher resolutions more effectively. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 15120 (122%)

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: Bandwidth is the max amount of data (measured in megabytes per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

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