Radeon HD 3850 256MB vs Radeon HD 4830 512MB

Intro

Compare that to the Radeon HD 4830 512MB, which features a clock frequency of 575 MHz and a GDDR3 memory frequency of 900 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It is comprised of 640(128x5) SPUs, 32 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 4830 512MB		95 Watts
	Difference: 20 Watts (27%)

Memory Bandwidth

The Radeon HD 4830 512MB, in theory, should be a bit faster than the Radeon HD 3850 256MB in general. (explain)

Radeon HD 4830 512MB		57600 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 4608 (9%)

Texel Rate

The Radeon HD 4830 512MB is a lot (approximately 72%) better at anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 4830 512MB		18400 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 7712 (72%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 3850 256MB is superior to the Radeon HD 4830 512MB, though not by far. (explain)

Radeon HD 3850 256MB		10688 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 1488 (16%)

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 data (in units of MB per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better 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 worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.