Radeon HD 3870 X2 512MB vs Radeon HD 6770

Intro

Compare those specs to the Radeon HD 6770, which makes use of a 40 nm design. ATi has set the core frequency at 900 MHz. The GDDR5 RAM works at a speed of 1050 MHz on this particular card. It features 800 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 X2 512MB is 71% quicker than the Radeon HD 6770 overall, due to its greater data rate. (explain)

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

Texel Rate

The Radeon HD 6770 should be much (about 36%) faster with regards to 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

The Radeon HD 3870 X2 512MB should be quite a bit (about 83%) more effective at full screen anti-aliasing than the Radeon HD 6770, and capable of handling higher screen resolutions better. (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 maximum amount of data (in units of MB per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 applied in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.