Radeon HD 4550 512MB vs Radeon HD 5450

Intro

Compare those specifications to the Radeon HD 5450, which features a clock frequency of 650 MHz and a DDR3 memory frequency of 800 MHz. It also features a 64-bit bus, and uses a 40 nm design. It is made up of 80(16x5) SPUs, 8 Texture Address Units, and 4 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5450		19 Watts
Radeon HD 4550 512MB		25 Watts
	Difference: 6 Watts (32%)

Memory Bandwidth

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

Texel Rate

The Radeon HD 5450 is a bit (more or less 8%) better at texture filtering than the Radeon HD 4550 512MB. (explain)

Radeon HD 5450		5200 Mtexels/sec
Radeon HD 4550 512MB		4800 Mtexels/sec
	Difference: 400 (8%)

Pixel Rate

The Radeon HD 5450 should be a bit (more or less 8%) better at full screen anti-aliasing than the Radeon HD 4550 512MB, and also capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 5450		2600 Mpixels/sec
Radeon HD 4550 512MB		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 max amount of data (in units of MB per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the bus width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.