Radeon HD 3850 X2 vs Radeon HD 4750

Intro

Compare those specifications to the Radeon HD 4750, which uses a 40 nm design. AMD has set the core frequency at 730 MHz. The GDDR5 memory runs at a frequency of 800 MHz on this 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

Memory Bandwidth

Performance-wise, the Radeon HD 3850 X2 should in theory be a lot superior to the Radeon HD 4750 in general. (explain)

Radeon HD 3850 X2		105984 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 54784 (107%)

Texel Rate

The Radeon HD 4750 is a little bit (approximately 9%) better at anisotropic filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 4750		23360 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 1984 (9%)

Pixel Rate

The Radeon HD 3850 X2 should be quite a bit (more or less 83%) better at FSAA than the Radeon HD 4750, and should be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4750		11680 Mpixels/sec
	Difference: 9696 (83%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (measured in MB per second) that can be transported across the external memory interface in a second. The number is worked out by multiplying the card's bus width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. 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 also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.