Radeon HD 4550 256MB vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which comes with a core clock frequency of 775 MHz and a GDDR5 memory frequency of 1000 MHz. It also makes use of a 256-bit bus, and uses a 40 nm design. It features 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 4550 256MB		25 Watts
Radeon HD 6850		127 Watts
	Difference: 102 Watts (408%)

Memory Bandwidth

In theory, the Radeon HD 6850 is 900% faster than the Radeon HD 4550 256MB in general, because of its greater data rate. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 115200 (900%)

Texel Rate

The Radeon HD 6850 is quite a bit (approximately 675%) faster with regards to texture filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 32400 (675%)

Pixel Rate

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

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 22400 (933%)

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 megabytes per second) that can be transferred across the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, 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 number of texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the card will be at 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 write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core clock speed. 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 also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.