Radeon HD 3850 256MB vs Radeon HD 3870 512MB

Intro

Compare all of that to the Radeon HD 3870 512MB, which features a GPU core clock speed of 775 MHz, and 512 MB of GDDR3 RAM running at 900 MHz through a 256-bit bus. It also is made up of 320(64x5) Stream Processors, 16 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		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 256MB overall. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 4608 (9%)

Texel Rate

The Radeon HD 3870 512MB is a little bit (about 16%) better at anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 3870 512MB		12400 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 1712 (16%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 512MB is the winner, but only just. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 3850 256MB		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 information (counted in megabytes per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 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 higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.