Radeon HD 4830 1GB vs Radeon HD 6750 1GB

Intro

Compare that to the Radeon HD 6750 1GB, which uses a 40 nm design. AMD has clocked the core speed at 725 MHz. The GDDR5 RAM is set to run at a frequency of 1000 MHz on this card. It features 720 SPUs along with 36 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750 1GB		86 Watts
Radeon HD 4830 1GB		95 Watts
	Difference: 9 Watts (10%)

Memory Bandwidth

In theory, the Radeon HD 6750 1GB is 11% quicker than the Radeon HD 4830 1GB overall, due to its higher data rate. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 6400 (11%)

Texel Rate

The Radeon HD 6750 1GB will be much (approximately 42%) more effective at anisotropic filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 7700 (42%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6750 1GB is superior to the Radeon HD 4830 1GB, and very much so. (explain)

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 2400 (26%)

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 data (counted in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, it 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 high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to the local memory in a 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 called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel 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 get to the maximum fill rate.