Radeon HD 4550 256MB vs Radeon HD 5550

Intro

Compare that to the Radeon HD 5550, which uses a 40 nm design. AMD has set the core speed at 550 MHz. The DDR2 RAM runs at a frequency of 400 MHz on this specific model. It features 320(64x5) SPUs as well as 16 TAUs and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Both cards have exactly the same bandwidth, so in theory they should have the same performance. (explain)

Texel Rate

The Radeon HD 5550 is much (approximately 83%) more effective at AF than the Radeon HD 4550 256MB. (explain)

Radeon HD 5550		8800 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 4000 (83%)

Pixel Rate

The Radeon HD 5550 is a lot (about 83%) more effective at full screen anti-aliasing than the Radeon HD 4550 256MB, and capable of handling higher resolutions while still performing well. (explain)

Radeon HD 5550		4400 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 2000 (83%)

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 max amount of data (in units of megabytes per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. 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 high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs 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, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.