Radeon HD 3870 512MB vs Radeon HD 4730

Intro

Compare all of that to the Radeon HD 4730, which uses a 55 nm design. AMD has set the core frequency at 700 MHz. The GDDR5 memory runs at a frequency of 900 MHz on this card. It features 640(128x5) SPUs along with 32 TAUs and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 4730		140 Watts
	Difference: 34 Watts (32%)

Memory Bandwidth

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

Texel Rate

The Radeon HD 4730 is quite a bit (approximately 81%) faster with regards to texture filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 4730		22400 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 10000 (81%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 3870 512MB is the winner, by far. (explain)

Radeon HD 3870 512MB		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 data (in units of MB per second) that can be transferred across the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster 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 number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.