Radeon HD 3850 512MB vs Radeon HD 4770

Intro

Compare that to the Radeon HD 4770, which features GPU clock speed of 750 MHz, and 512 MB of GDDR5 memory running at 800 MHz through a 128-bit bus. It also is made up of 640(128x5) Stream Processors, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 512MB		75 Watts
Radeon HD 4770		80 Watts
	Difference: 5 Watts (7%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3850 512MB is 4% faster than the Radeon HD 4770 in general, due to its greater data rate. (explain)

Radeon HD 3850 512MB		52992 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 1792 (4%)

Texel Rate

The Radeon HD 4770 is a lot (more or less 125%) faster with regards to texture filtering than the Radeon HD 3850 512MB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 13312 (125%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 4770 is the winner, but only just. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 3850 512MB		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 largest amount of data (measured in megabytes per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. In the case of DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core speed of the card. 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 lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.