Radeon HD 3850 1GB vs Radeon HD 4850 X2 512MB

Intro

Compare those specs to the Radeon HD 4850 X2 512MB, which makes use of a 55 nm design. AMD has clocked the core speed at 625 MHz. The GDDR3 RAM is set to run at a frequency of 993 MHz on this specific model. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 1GB		75 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 175 Watts (233%)

Memory Bandwidth

In theory, the Radeon HD 4850 X2 512MB should perform a lot faster than the Radeon HD 3850 1GB overall. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 3850 1GB		52992 MB/sec
	Difference: 74112 (140%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a lot (more or less 368%) better at texture filtering than the Radeon HD 3850 1GB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 3850 1GB		10688 Mtexels/sec
	Difference: 39312 (368%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4850 X2 512MB is a better choice, by a large margin. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 3850 1GB		10688 Mpixels/sec
	Difference: 9312 (87%)

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: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be moved across the external memory interface in a second. It is calculated by multiplying the interface width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster 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 in one second. This number is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics 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 can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.