Radeon HD 3850 256MB vs Radeon HD 3870 512MB

Intro

Compare all that to the Radeon HD 3870 512MB, which uses a 55 nm design. AMD has clocked the core frequency at 775 MHz. The GDDR3 memory is set to run at a speed of 900 MHz on this specific card. It features 320(64x5) SPUs along with 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

As far as performance goes, the Radeon HD 3870 512MB should in theory be just a bit superior to 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 bit (more or less 16%) more effective 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 a high resolution is important to you, then the Radeon HD 3870 512MB is superior to the Radeon HD 3850 256MB, not by a very large margin though. (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: Bandwidth is the max amount of information (measured in MB per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range 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 calculated by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka 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, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.