Radeon HD 4850 2GB vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which comes with a clock frequency of 775 MHz and a GDDR5 memory speed of 1000 MHz. It also makes use of a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 960 SPUs, 48 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 2GB		110 Watts
Radeon HD 6850		127 Watts
	Difference: 17 Watts (15%)

Memory Bandwidth

In theory, the Radeon HD 6850 should be much faster than the Radeon HD 4850 2GB overall. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 64448 (101%)

Texel Rate

The Radeon HD 6850 will be much (about 49%) faster with regards to texture filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 12200 (49%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6850 is a better choice, by a large margin. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 14800 (148%)

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 (in units of MB per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 once 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 AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the 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 number of pixels the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the card's 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 - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.