Radeon HD 4550 256MB vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which has GPU core speed of 840 MHz, and 1024 MB of GDDR5 RAM set to run at 1050 MHz through a 256-bit bus. It also features 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 256MB		25 Watts
Radeon HD 6790		150 Watts
	Difference: 125 Watts (500%)

Memory Bandwidth

Performance-wise, the Radeon HD 6790 should in theory be much better than the Radeon HD 4550 256MB overall. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 121600 (950%)

Texel Rate

The Radeon HD 6790 should be a lot (more or less 600%) more effective at texture filtering than the Radeon HD 4550 256MB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 28800 (600%)

Pixel Rate

The Radeon HD 6790 is quite a bit (more or less 460%) better at anti-aliasing than the Radeon HD 4550 256MB, and able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4550 256MB		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 maximum amount of information (counted in MB per second) that can be transferred over the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This number is worked out 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs 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 many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.