Radeon HD 3870 1GB vs Radeon HD 4830 512MB

Intro

Compare those specs to the Radeon HD 4830 512MB, which has GPU core speed of 575 MHz, and 512 MB of GDDR3 memory set to run at 900 MHz through a 256-bit bus. It also is comprised of 640(128x5) Stream Processors, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

The Radeon HD 3870 1GB should theoretically be much faster than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

The Radeon HD 4830 512MB is a lot (more or less 48%) faster with regards to anisotropic filtering than the Radeon HD 3870 1GB. (explain)

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

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 1GB is a better choice, by a large margin. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon HD 4830 512MB		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 (measured in MB per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, 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 amount of texture map elements (texels) that can be 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs 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 fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.