Radeon HD 4550 256MB vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which features core speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 Texture Address Units 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 7990		375 Watts
	Difference: 350 Watts (1400%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7990 should be 4400% faster than the Radeon HD 4550 256MB overall, due to its greater bandwidth. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 563200 (4400%)

Texel Rate

The Radeon HD 7990 is a lot (approximately 4967%) more effective at texture filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 238400 (4967%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7990 is a better choice, and very much so. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 58400 (2433%)

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: Bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.