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

Intro

Compare those specs to the Radeon HD 4850 X2 512MB, which comes with core speeds of 625 MHz on the GPU, and 993 MHz on the 512 MB of GDDR3 memory. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

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

Theoretically speaking, the Radeon HD 4850 X2 512MB should perform much 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 quite a bit (more or less 368%) more effective at AF 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 lots of anti-aliasing is important to you, then the Radeon HD 4850 X2 512MB is the winner, and very much so. (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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be moved past the external memory interface within a second. It's worked out by multiplying the interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can 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 Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.