Radeon HD 3870 512MB vs Radeon HD 4830 1GB

Intro

Compare all that to the Radeon HD 4830 1GB, which makes use of a 55 nm design. AMD has set the core speed at 575 MHz. The GDDR4 RAM runs at a speed of 900 MHz on this specific card. It features 640(128x5) SPUs along with 32 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 11 Watts (12%)

Memory Bandwidth

Both cards have the exact same bandwidth, so theoretically they should perform exactly the same. (explain)

Texel Rate

The Radeon HD 4830 1GB will be much (approximately 48%) faster with regards to AF than the Radeon HD 3870 512MB. (explain)

Radeon HD 4830 1GB		18400 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 6000 (48%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3870 512MB is superior to the Radeon HD 4830 1GB, by a large margin. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 3200 (35%)

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 information (in units of megabytes per second) that can be moved over the external memory interface within a second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 amount of texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher 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 a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the clock 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 fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.