Radeon HD 4550 512MB vs Radeon HD 6950 2GB

Intro

Compare all of that to the Radeon HD 6950 2GB, which features a clock speed of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 256-bit memory bus, and makes use of a 40 nm design. It is comprised of 1408 SPUs, 88 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 512MB		25 Watts
Radeon HD 6950 2GB		200 Watts
	Difference: 175 Watts (700%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6950 2GB should in theory be quite a bit better than the Radeon HD 4550 512MB in general. (explain)

Radeon HD 6950 2GB		160000 MB/sec
Radeon HD 4550 512MB		12800 MB/sec
	Difference: 147200 (1150%)

Texel Rate

The Radeon HD 6950 2GB is much (more or less 1367%) more effective at AF than the Radeon HD 4550 512MB. (explain)

Radeon HD 6950 2GB		70400 Mtexels/sec
Radeon HD 4550 512MB		4800 Mtexels/sec
	Difference: 65600 (1367%)

Pixel Rate

The Radeon HD 6950 2GB should be a lot (about 967%) more effective at full screen anti-aliasing than the Radeon HD 4550 512MB, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 6950 2GB		25600 Mpixels/sec
Radeon HD 4550 512MB		2400 Mpixels/sec
	Difference: 23200 (967%)

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 maximum amount of information (in units of MB per second) that can be transferred across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, the result should 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, 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 higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out 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 drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.