Radeon HD 3870 512MB vs Radeon HD 6770

Intro

Compare those specifications to the Radeon HD 6770, which comes with a core clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 128-bit bus, and uses a 40 nm design. It is comprised of 800 SPUs, 40 Texture Address Units, and 16 Raster Operation 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

Theoretically speaking, the Radeon HD 6770 should be just a bit faster than the Radeon HD 3870 512MB overall. (explain)

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

Texel Rate

The Radeon HD 6770 will be quite a bit (about 190%) more effective 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 using a high resolution is important to you, then the Radeon HD 6770 is superior to the Radeon HD 3870 512MB, but 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 (in units of megabytes per second) that can be moved past the external memory interface within a second. The number is worked out by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If 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 number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units 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 output rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.