Radeon HD 3850 512MB vs Radeon HD 4750

Intro

Compare that to the Radeon HD 4750, which uses a 40 nm design. AMD has clocked the core speed at 730 MHz. The GDDR5 memory runs at a frequency of 800 MHz on this specific card. It features 640(128x5) SPUs along with 32 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

The Radeon HD 3850 512MB, in theory, should perform a bit faster than the Radeon HD 4750 overall. (explain)

Radeon HD 3850 512MB		52992 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 1792 (4%)

Texel Rate

The Radeon HD 4750 will be quite a bit (approximately 119%) more effective at AF than the Radeon HD 3850 512MB. (explain)

Radeon HD 4750		23360 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 12672 (119%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4750 is the winner, but it probably won't make a huge difference. (explain)

Radeon HD 4750		11680 Mpixels/sec
Radeon HD 3850 512MB		10688 Mpixels/sec
	Difference: 992 (9%)

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 (in units of megabytes per second) that can be transported over the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is calculated 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 video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.