Radeon HD 4550 256MB vs Radeon HD 4650 512MB

Intro

Compare all that to the Radeon HD 4650 512MB, which has core speeds of 600 MHz on the GPU, and 500 MHz on the 512 MB of DDR2 RAM. 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

Theoretically, the Radeon HD 4650 512MB should perform quite a bit faster than the Radeon HD 4550 256MB overall. (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 is quite a bit (approximately 300%) more effective 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

If running with a high screen resolution is important to you, then the Radeon HD 4650 512MB is a better choice, and very much so. (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: Memory bandwidth is the maximum amount of information (counted in megabytes per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total amount of 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 applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.