Radeon HD 3870 X2 1GB vs Radeon HD 6770 1GB

Intro

Compare that to the Radeon HD 6770 1GB, which makes use of a 40 nm design. AMD has clocked the core frequency at 900 MHz. The GDDR5 memory is set to run at a frequency of 1050 MHz on this particular card. It features 800 SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 3870 X2 1GB should theoretically perform quite a bit faster than the Radeon HD 6770 1GB overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 76928 (114%)

Texel Rate

The Radeon HD 6770 1GB will be quite a bit (more or less 36%) better at texture filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 6770 1GB		36000 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 9600 (36%)

Pixel Rate

The Radeon HD 3870 X2 1GB is much (about 83%) more effective at full screen anti-aliasing than the Radeon HD 6770 1GB, and also should be able to handle higher screen resolutions better. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 6770 1GB		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: Memory bandwidth is the largest amount of information (in units of megabytes per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the 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 number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs 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 is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.