Radeon HD 3850 256MB vs Radeon HD 4830 1GB

Intro

Compare all of that to the Radeon HD 4830 1GB, which features core speeds of 575 MHz on the GPU, and 900 MHz on the 1024 MB of GDDR4 RAM. It features 640(128x5) SPUs along with 32 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 4830 1GB		95 Watts
	Difference: 20 Watts (27%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4830 1GB will be 9% faster than the Radeon HD 3850 256MB overall, because of its higher bandwidth. (explain)

Radeon HD 4830 1GB		57600 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 4608 (9%)

Texel Rate

The Radeon HD 4830 1GB is much (more or less 72%) more effective at texture filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 4830 1GB		18400 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 7712 (72%)

Pixel Rate

The Radeon HD 3850 256MB is just a bit (about 16%) faster with regards to full screen anti-aliasing than the Radeon HD 4830 1GB, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3850 256MB		10688 Mpixels/sec
Radeon HD 4830 1GB		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 maximum amount of data (in units of megabytes per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

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