Radeon HD 4830 1GB vs Radeon HD 6870

Intro

Compare all of that to the Radeon HD 6870, which has a GPU core clock speed of 900 MHz, and 1024 MB of GDDR5 memory set to run at 1050 MHz through a 256-bit bus. It also is made up of 1120 SPUs, 56 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 6870		151 Watts
	Difference: 56 Watts (59%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6870 is 133% quicker than the Radeon HD 4830 1GB overall, due to its higher data rate. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 76800 (133%)

Texel Rate

The Radeon HD 6870 should be a lot (more or less 174%) more effective at anisotropic filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 32000 (174%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6870 is the winner, and very much so. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4830 1GB		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: Memory bandwidth is the maximum amount of data (measured in MB per second) that can be moved past the external memory interface within a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 are processed per second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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