Radeon HD 3850 X2 vs Radeon HD 7770

Intro

Compare all that to the Radeon HD 7770, which uses a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 memory is set to run at a speed of 1125 MHz on this particular model. It features 640 SPUs as well as 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3850 X2 should perform much faster than the Radeon HD 7770 overall. (explain)

Radeon HD 3850 X2		105984 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 33984 (47%)

Texel Rate

The Radeon HD 7770 is a lot (approximately 87%) more effective at texture filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 18624 (87%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 3850 X2 is the winner, by far. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 7770		16000 Mpixels/sec
	Difference: 5376 (34%)

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 information (measured in MB per second) that can be transferred past the external memory interface in one second. It's worked out by multiplying the interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum 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 better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.