Radeon HD 3850 512MB vs Radeon HD 3870 512MB

Intro

Compare those specifications to the Radeon HD 3870 512MB, which has GPU core speed of 775 MHz, and 512 MB of GDDR3 RAM running at 900 MHz through a 256-bit bus. It also is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 512MB		75 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 31 Watts (41%)

Memory Bandwidth

Performance-wise, the Radeon HD 3870 512MB should in theory be a bit superior to the Radeon HD 3850 512MB overall. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 4608 (9%)

Texel Rate

The Radeon HD 3870 512MB should be a small bit (more or less 16%) more effective at texture filtering than the Radeon HD 3850 512MB. (explain)

Radeon HD 3870 512MB		12400 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 1712 (16%)

Pixel Rate

The Radeon HD 3870 512MB should be a small bit (more or less 16%) more effective at full screen anti-aliasing than the Radeon HD 3850 512MB, and capable of handling higher resolutions better. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 3850 512MB		10688 Mpixels/sec
	Difference: 1712 (16%)

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 MB per second) that can be transported past the external memory interface within a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.