Radeon HD 5850 vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which features GPU core speed of 775 MHz, and 1024 MB of GDDR5 memory set to run at 1000 MHz through a 256-bit bus. It also features 960 SPUs, 48 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6850		127 Watts
Radeon HD 5850		151 Watts
	Difference: 24 Watts (19%)

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so in theory they should perform exactly the same. (explain)

Texel Rate

The Radeon HD 5850 should be much (more or less 40%) more effective at anisotropic filtering than the Radeon HD 6850. (explain)

Radeon HD 5850		52200 Mtexels/sec
Radeon HD 6850		37200 Mtexels/sec
	Difference: 15000 (40%)

Pixel Rate

The Radeon HD 6850 is a bit (about 7%) more effective at anti-aliasing than the Radeon HD 5850, and also will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 5850		23200 Mpixels/sec
	Difference: 1600 (7%)

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 transferred past the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total number of texture units of the card 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 applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.