Radeon HD 3850 1GB vs Radeon HD 3870 512MB

Intro

Compare those specs to the Radeon HD 3870 512MB, which comes with clock speeds of 775 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 320(64x5) SPUs as well as 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

Theoretically speaking, the Radeon HD 3870 512MB should be a little bit faster than the Radeon HD 3850 1GB overall. (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 will be just a bit (approximately 16%) better at AF 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 a high resolution is important to you, then the Radeon HD 3870 512MB is a better choice, not by a very large margin though. (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 maximum amount of data (in units of megabytes per second) that can be moved over the external memory interface within a second. The number is worked out by multiplying the interface width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core 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 per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.