Radeon HD 4830 512MB vs Radeon HD 6870

Intro

Compare all of that to the Radeon HD 6870, which has a clock frequency of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also makes use of a 256-bit memory bus, and makes use of a 40 nm design. It is comprised of 1120 SPUs, 56 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 6870		151 Watts
	Difference: 56 Watts (59%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6870 should theoretically be a lot superior to the Radeon HD 4830 512MB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 76800 (133%)

Texel Rate

The Radeon HD 6870 is much (more or less 174%) better at anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 32000 (174%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6870 is superior to the Radeon HD 4830 512MB, by a large margin. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 19600 (213%)

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 MB per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, 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 texture map elements (texels) that are processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.