Radeon HD 4550 256MB vs Radeon HD 6870

Intro

Compare all of that to the Radeon HD 6870, which features a clock speed of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also uses a 256-bit bus, and makes use of a 40 nm design. It is comprised of 1120 SPUs, 56 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 256MB		25 Watts
Radeon HD 6870		151 Watts
	Difference: 126 Watts (504%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6870 should in theory be a lot better than the Radeon HD 4550 256MB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 121600 (950%)

Texel Rate

The Radeon HD 6870 will be much (about 950%) faster with regards to texture filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 45600 (950%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 6870 is the winner, by far. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 26400 (1100%)

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 max amount of information (in units of megabytes per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the bus width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units of the card 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 per second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.