Radeon HD 4830 512MB vs Radeon HD 6750 1GB

Intro

Compare all of that to the Radeon HD 6750 1GB, which features GPU clock speed of 725 MHz, and 1024 MB of GDDR5 RAM set to run at 1000 MHz through a 128-bit bus. It also is made up of 720 SPUs, 36 TAUs, 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 512MB		95 Watts
	Difference: 9 Watts (10%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6750 1GB is 11% faster than the Radeon HD 4830 512MB overall, because of its higher data rate. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 6400 (11%)

Texel Rate

The Radeon HD 6750 1GB is much (about 42%) faster with regards to anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 7700 (42%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 6750 1GB is the winner, and very much so. (explain)

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 4830 512MB		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 (in units of megabytes per second) that can be transported 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 it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount 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 drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.