Radeon HD 3850 256MB vs Radeon HD 4850 1GB

Intro

Compare all of that to the Radeon HD 4850 1GB, which makes use of a 55 nm design. AMD has set the core frequency at 625 MHz. The GDDR4 RAM is set to run at a frequency of 993 MHz on this particular model. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 4850 1GB		110 Watts
	Difference: 35 Watts (47%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 1GB should theoretically be a small bit superior to the Radeon HD 3850 256MB in general. (explain)

Radeon HD 4850 1GB		63552 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 10560 (20%)

Texel Rate

The Radeon HD 4850 1GB should be quite a bit (about 134%) faster with regards to anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 4850 1GB		25000 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 14312 (134%)

Pixel Rate

The Radeon HD 3850 256MB is a little bit (more or less 7%) faster with regards to anti-aliasing than the Radeon HD 4850 1GB, and should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 3850 256MB		10688 Mpixels/sec
Radeon HD 4850 1GB		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: Bandwidth is the largest amount of data (measured in megabytes per second) that can be transferred over the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, 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 anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.