Radeon HD 3850 X2 vs Radeon HD 4770

Intro

Compare that to the Radeon HD 4770, which comes with a clock frequency of 750 MHz and a GDDR5 memory speed of 800 MHz. It also features a 128-bit memory bus, and makes use of a 40 nm design. It features 640(128x5) SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 3850 X2 should in theory perform a lot faster than the Radeon HD 4770 in general. (explain)

Radeon HD 3850 X2		105984 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 54784 (107%)

Texel Rate

The Radeon HD 4770 will be a small bit (more or less 12%) faster with regards to texture filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 2624 (12%)

Pixel Rate

The Radeon HD 3850 X2 will be quite a bit (more or less 78%) better at FSAA than the Radeon HD 4770, and able to handle higher resolutions better. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 9376 (78%)

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 maximum amount of information (in units of MB per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster 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 are processed per second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the video 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 most pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.