Radeon HD 4550 256MB vs Radeon HD 5450

Intro

Compare that to the Radeon HD 5450, which uses a 40 nm design. AMD has clocked the core speed at 650 MHz. The DDR3 memory works at a frequency of 800 MHz on this particular card. It features 80(16x5) SPUs as well as 8 Texture Address Units 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 the exact same memory bandwidth, so theoretically they should perform the same. (explain)

Texel Rate

The Radeon HD 5450 will be a little bit (about 8%) more effective at 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 a high resolution is important to you, then the Radeon HD 5450 is superior to the Radeon HD 4550 256MB, though not by far. (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: Bandwidth is the maximum amount of data (in units of MB per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 number of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the 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 the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.