Radeon HD 3850 1GB vs Radeon HD 4850 2GB

Intro

Compare those specs to the Radeon HD 4850 2GB, which comes with GPU clock speed of 625 MHz, and 2048 MB of GDDR4 memory running at 993 MHz through a 256-bit bus. It also is comprised of 800(160x5) Stream Processors, 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 2GB		110 Watts
	Difference: 35 Watts (47%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 2GB should in theory be a bit better than the Radeon HD 3850 1GB overall. (explain)

Radeon HD 4850 2GB		63552 MB/sec
Radeon HD 3850 1GB		52992 MB/sec
	Difference: 10560 (20%)

Texel Rate

The Radeon HD 4850 2GB should be quite a bit (approximately 134%) more effective at texture filtering than the Radeon HD 3850 1GB. (explain)

Radeon HD 4850 2GB		25000 Mtexels/sec
Radeon HD 3850 1GB		10688 Mtexels/sec
	Difference: 14312 (134%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 3850 1GB is a better choice, but only just. (explain)

Radeon HD 3850 1GB		10688 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 688 (7%)

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: Memory bandwidth is the largest amount of information (in units of megabytes per second) that can be transported past the external memory interface within a second. It is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster 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 texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.