Radeon HD 4830 1GB vs Radeon HD 6750 1GB

Intro

Compare those specifications to the Radeon HD 6750 1GB, which comes with clock speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 720 SPUs as well as 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

Performance-wise, the Radeon HD 6750 1GB should theoretically be a little bit better than the Radeon HD 4830 1GB overall. (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 is 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

The Radeon HD 6750 1GB is quite a bit (approximately 26%) better at AA than the Radeon HD 4830 1GB, and also will be able to handle higher resolutions better. (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: Memory bandwidth is the maximum amount of data (counted in megabytes per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one 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 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 most pixels that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill 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.