Radeon HD 5850 vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which comes with GPU clock speed of 775 MHz, and 1024 MB of GDDR5 memory running at 1000 MHz through a 256-bit bus. It also is comprised of 960 SPUs, 48 Texture Address Units, and 32 Raster Operation Units.

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

Texel Rate

The Radeon HD 5850 is much (about 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

If running with lots of anti-aliasing is important to you, then the Radeon HD 6850 is superior to the Radeon HD 5850, though not by far. (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: Memory bandwidth is the largest amount of data (counted in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If the card has DDR memory, the result should be multiplied by 2 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, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the 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 maximum number of pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.