Radeon HD 3850 256MB vs Radeon HD 4770

Intro

Compare those specs to the Radeon HD 4770, which has clock speeds of 750 MHz on the GPU, and 800 MHz on the 512 MB of GDDR5 RAM. It features 640(128x5) SPUs as well as 32 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 4770		80 Watts
	Difference: 5 Watts (7%)

Memory Bandwidth

The Radeon HD 3850 256MB should theoretically perform just a bit faster than the Radeon HD 4770 in general. (explain)

Radeon HD 3850 256MB		52992 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 1792 (4%)

Texel Rate

The Radeon HD 4770 is quite a bit (approximately 125%) more effective at AF than the Radeon HD 3850 256MB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 13312 (125%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4770 is the winner, not by a very large margin though. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 3850 256MB		10688 Mpixels/sec
	Difference: 1312 (12%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (counted in megabytes per second) that can be transferred over the external memory interface within a second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better 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 can be processed per second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.