Radeon HD 3850 256MB vs Radeon HD 4750

Intro

Compare all of that to the Radeon HD 4750, which has a clock speed of 730 MHz and a GDDR5 memory speed of 800 MHz. It also uses a 128-bit memory bus, and makes use of a 40 nm design. It is made up of 640(128x5) SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

As far as performance goes, the Radeon HD 3850 256MB should in theory be just a bit better than the Radeon HD 4750 in general. (explain)

Radeon HD 3850 256MB		52992 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 1792 (4%)

Texel Rate

The Radeon HD 4750 will be much (approximately 119%) more effective at anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 4750		23360 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 12672 (119%)

Pixel Rate

The Radeon HD 4750 will be a little bit (approximately 9%) better at full screen anti-aliasing than the Radeon HD 3850 256MB, and should be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 4750		11680 Mpixels/sec
Radeon HD 3850 256MB		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: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the bus width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This is worked out by multiplying the total amount of texture units 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 in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.