Radeon HD 4550 512MB vs Radeon HD 6790

Intro

Compare all that to the Radeon HD 6790, which has a clock frequency of 840 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 256-bit bus, and makes use of a 40 nm design. It is comprised of 800 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 512MB		25 Watts
Radeon HD 6790		150 Watts
	Difference: 125 Watts (500%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6790 will be 950% quicker than the Radeon HD 4550 512MB in general, because of its greater bandwidth. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4550 512MB		12800 MB/sec
	Difference: 121600 (950%)

Texel Rate

The Radeon HD 6790 is quite a bit (approximately 600%) faster with regards to AF than the Radeon HD 4550 512MB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4550 512MB		4800 Mtexels/sec
	Difference: 28800 (600%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6790 is superior to the Radeon HD 4550 512MB, by a large margin. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4550 512MB		2400 Mpixels/sec
	Difference: 11040 (460%)

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 information (in units of MB per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 number is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the card's 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 quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.