Radeon HD 3850 1GB vs Radeon HD 3870 512MB

Intro

Compare those specs to the Radeon HD 3870 512MB, which comes with a GPU core clock speed of 775 MHz, and 512 MB of GDDR3 memory set to run at 900 MHz through a 256-bit bus. It also is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 1GB		75 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 31 Watts (41%)

Memory Bandwidth

As far as performance goes, the Radeon HD 3870 512MB should in theory be just a bit superior to the Radeon HD 3850 1GB in general. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 3850 1GB		52992 MB/sec
	Difference: 4608 (9%)

Texel Rate

The Radeon HD 3870 512MB should be a small bit (about 16%) faster with regards to anisotropic filtering than the Radeon HD 3850 1GB. (explain)

Radeon HD 3870 512MB		12400 Mtexels/sec
Radeon HD 3850 1GB		10688 Mtexels/sec
	Difference: 1712 (16%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 3870 512MB is a better choice, though not by far. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 3850 1GB		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: Memory bandwidth is the largest amount of information (counted in megabytes per second) that can be transferred past the external memory interface in a second. The number is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of 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 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 ability to get to the max fill rate.