Radeon HD 3870 1GB vs Radeon HD 4830 1GB

Intro

Compare those specs to the Radeon HD 4830 1GB, which comes with core clock 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 4830 1GB		95 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 11 Watts (12%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 1GB should perform a lot faster than the Radeon HD 4830 1GB in general. (explain)

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

Texel Rate

The Radeon HD 4830 1GB will be a lot (more or less 48%) more effective at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

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

Pixel Rate

The Radeon HD 3870 1GB will be much (approximately 35%) more effective at FSAA than the Radeon HD 4830 1GB, and should be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 3870 1GB		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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transferred past the external memory interface in a second. It's calculated by multiplying the card's interface 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 card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines 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 many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.