Radeon HD 3870 512MB vs Radeon HD 6770

Intro

Compare that to the Radeon HD 6770, which makes use of a 40 nm design. AMD has clocked the core speed at 900 MHz. The GDDR5 memory is set to run at a frequency of 1050 MHz on this specific model. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 6770		108 Watts
	Difference: 2 Watts (2%)

Memory Bandwidth

In theory, the Radeon HD 6770 should be 17% quicker than the Radeon HD 3870 512MB overall, because of its higher bandwidth. (explain)

Radeon HD 6770		67200 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 9600 (17%)

Texel Rate

The Radeon HD 6770 is a lot (approximately 190%) better at AF than the Radeon HD 3870 512MB. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 23600 (190%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6770 is the winner, though not by far. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 2000 (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 megabytes per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the bus width by the speed of its memory. If it uses DDR memory, it must 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the 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 maximum amount of pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.