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

Intro

Compare all of that to the Radeon HD 4850 X2 1GB, which comes with a clock frequency of 625 MHz and a GDDR3 memory speed of 993 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, 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 4850 X2 1GB		250 Watts
	Difference: 175 Watts (233%)

Memory Bandwidth

The Radeon HD 4850 X2 1GB should theoretically be a lot faster than the Radeon HD 3850 512MB overall. (explain)

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

Texel Rate

The Radeon HD 4850 X2 1GB will be a lot (about 368%) faster with regards to texture filtering than the Radeon HD 3850 512MB. (explain)

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

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 4850 X2 1GB is a better choice, by a large margin. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 3850 512MB		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: Memory bandwidth is the largest amount of information (counted in MB per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.