Radeon HD 3850 512MB vs Radeon HD 4770

Intro

Compare those specs to the Radeon HD 4770, which makes use of a 40 nm design. AMD has set the core frequency at 750 MHz. The GDDR5 memory is set to run at a frequency of 800 MHz on this particular model. 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 512MB		75 Watts
Radeon HD 4770		80 Watts
	Difference: 5 Watts (7%)

Memory Bandwidth

In theory, the Radeon HD 3850 512MB is 4% quicker than the Radeon HD 4770 overall, because of 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 quite a bit (about 125%) more effective at anisotropic 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

The Radeon HD 4770 should be a bit (approximately 12%) more effective at FSAA than the Radeon HD 3850 512MB, and will be capable of handling higher screen resolutions better. (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: Bandwidth is the max amount of data (in units of MB per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the bus width by its memory speed. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total number of 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.