Radeon HD 4550 256MB vs Radeon HD 6990

Intro

Compare that to the Radeon HD 6990, which has core speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs as well as 96 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 256MB		25 Watts
Radeon HD 6990		375 Watts
	Difference: 350 Watts (1400%)

Memory Bandwidth

In theory, the Radeon HD 6990 should perform much faster than the Radeon HD 4550 256MB overall. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 307200 (2400%)

Texel Rate

The Radeon HD 6990 is quite a bit (approximately 3220%) faster with regards to anisotropic filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 154560 (3220%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6990 is a better choice, and very much so. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 50720 (2113%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of data (measured in MB per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.