Radeon HD 3870 X2 512MB vs Radeon HD 6770

Intro

Compare those specifications to the Radeon HD 6770, which comes with GPU core speed of 900 MHz, and 512 MB of GDDR5 RAM set to run at 1050 MHz through a 128-bit bus. It also 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

Memory Bandwidth

The Radeon HD 3870 X2 512MB should in theory be quite a bit faster than the Radeon HD 6770 in general. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon HD 6770		67200 MB/sec
	Difference: 48000 (71%)

Texel Rate

The Radeon HD 6770 will be a lot (approximately 36%) more effective at anisotropic filtering than the Radeon HD 3870 X2 512MB. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 9600 (36%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 3870 X2 512MB is the winner, by far. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 6770		14400 Mpixels/sec
	Difference: 12000 (83%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the largest amount of data (in units of megabytes per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the interface width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total 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 processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the clock speed of the card. 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 many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.