Radeon HD 3870 X2 1GB vs Radeon HD 5770

Intro

Compare those specs to the Radeon HD 5770, which comes with GPU clock speed of 850 MHz, and 1024 MB of GDDR5 memory running at 1200 MHz through a 128-bit bus. It also features 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 3870 X2 1GB, in theory, should perform a lot faster than the Radeon HD 5770 overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon HD 5770		76800 MB/sec
	Difference: 67328 (88%)

Texel Rate

The Radeon HD 5770 should be a lot (approximately 29%) more effective at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 5770		34000 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 7600 (29%)

Pixel Rate

The Radeon HD 3870 X2 1GB will be quite a bit (approximately 94%) more effective at FSAA than the Radeon HD 5770, and also capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 5770		13600 Mpixels/sec
	Difference: 12800 (94%)

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 data (counted in megabytes per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the 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 texture map elements (texels) that are applied per second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.