Radeon HD 4830 512MB vs Radeon HD 6850

Intro

Compare all that to the Radeon HD 6850, which comes with GPU core speed of 775 MHz, and 1024 MB of GDDR5 RAM set to run at 1000 MHz through a 256-bit bus. It also is comprised of 960 Stream Processors, 48 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 6850		127 Watts
	Difference: 32 Watts (34%)

Memory Bandwidth

In theory, the Radeon HD 6850 is 122% quicker than the Radeon HD 4830 512MB overall, due to its greater data rate. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 70400 (122%)

Texel Rate

The Radeon HD 6850 will be quite a bit (approximately 102%) more effective at anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 18800 (102%)

Pixel Rate

The Radeon HD 6850 will be a lot (more or less 170%) better at AA than the Radeon HD 4830 512MB, and able to handle higher screen resolutions more effectively. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 15600 (170%)

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 across the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.