Radeon HD 3850 256MB vs Radeon HD 4770

Intro

Compare that to the Radeon HD 4770, which comes with core speeds of 750 MHz on the GPU, and 800 MHz on the 512 MB of GDDR5 memory. It features 640(128x5) SPUs as well as 32 Texture Address Units and 16 ROPs.

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

As far as performance goes, the Radeon HD 3850 256MB should theoretically be just a bit better than the Radeon HD 4770 overall. (explain)

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

Texel Rate

The Radeon HD 4770 should be much (approximately 125%) better 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

The Radeon HD 4770 should be a small bit (more or less 12%) better at full screen anti-aliasing than the Radeon HD 3850 256MB, and capable of handling higher resolutions more effectively. (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: Bandwidth is the largest amount of information (in units of megabytes per second) that can be transferred across the external memory interface in a second. The number is calculated by multiplying the bus width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better 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 applied in one second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.