Radeon HD 4550 256MB vs Radeon HD 4650 512MB

Intro

Compare those specs to the Radeon HD 4650 512MB, which makes use of a 55 nm design. AMD has set the core frequency at 600 MHz. The DDR2 memory works at a speed of 500 MHz on this particular model. It features 320(64x5) SPUs as well as 32 TAUs and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 256MB		25 Watts
Radeon HD 4650 512MB		55 Watts
	Difference: 30 Watts (120%)

Memory Bandwidth

In theory, the Radeon HD 4650 512MB is 25% quicker than the Radeon HD 4550 256MB in general, because of its greater bandwidth. (explain)

Radeon HD 4650 512MB		16000 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 3200 (25%)

Texel Rate

The Radeon HD 4650 512MB will be a lot (about 300%) better at texture filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 4650 512MB		19200 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 14400 (300%)

Pixel Rate

The Radeon HD 4650 512MB is much (about 100%) more effective at anti-aliasing than the Radeon HD 4550 256MB, and will be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 4650 512MB		4800 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 2400 (100%)

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 largest amount of data (counted in MB per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip 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 - also called 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 memory bandwidth is, the lower the ability to reach the max fill rate.