Radeon HD 3870 1GB vs Radeon HD 4730

Intro

Compare those specs to the Radeon HD 4730, which comes with a GPU core clock speed of 700 MHz, and 512 MB of GDDR5 memory set to run at 900 MHz through a 128-bit bus. It also is made up of 640(128x5) Stream Processors, 32 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
Radeon HD 4730		140 Watts
	Difference: 34 Watts (32%)

Memory Bandwidth

Theoretically, the Radeon HD 3870 1GB should perform much faster than the Radeon HD 4730 overall. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 4730		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

The Radeon HD 4730 will be quite a bit (more or less 81%) more effective at AF than the Radeon HD 3870 1GB. (explain)

Radeon HD 4730		22400 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 10000 (81%)

Pixel Rate

The Radeon HD 3870 1GB will be much (approximately 121%) more effective at anti-aliasing than the Radeon HD 4730, and also will be capable of handling higher screen resolutions better. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon HD 4730		5600 Mpixels/sec
	Difference: 6800 (121%)

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 max amount of information (measured in MB per second) that can be transported over the external memory interface in one second. It is calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, 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 AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.