Radeon HD 4830 1GB vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which makes use of a 40 nm design. AMD has set the core speed at 840 MHz. The GDDR5 RAM works at a frequency of 1050 MHz on this particular card. It features 800 SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 6790		150 Watts
	Difference: 55 Watts (58%)

Memory Bandwidth

In theory, the Radeon HD 6790 should be 133% quicker than the Radeon HD 4830 1GB in general, due to its greater data rate. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 76800 (133%)

Texel Rate

The Radeon HD 6790 is quite a bit (approximately 83%) better at anisotropic filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 15200 (83%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 6790 is the winner, and very much so. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 4240 (46%)

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

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics 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 that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called 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 of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.