Radeon HD 4550 256MB vs Radeon HD 5450

Intro

Compare those specs to the Radeon HD 5450, which features a clock speed of 650 MHz and a DDR3 memory speed of 800 MHz. It also uses a 64-bit bus, and makes use of a 40 nm design. It features 80(16x5) SPUs, 8 TAUs, and 4 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5450		19 Watts
Radeon HD 4550 256MB		25 Watts
	Difference: 6 Watts (32%)

Memory Bandwidth

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

Texel Rate

The Radeon HD 5450 is a bit (about 8%) faster with regards to AF than the Radeon HD 4550 256MB. (explain)

Radeon HD 5450		5200 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 400 (8%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 5450 is a better choice, but only just. (explain)

Radeon HD 5450		2600 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 200 (8%)

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 (counted in megabytes per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.