Radeon HD 4670 512MB vs Radeon HD 6750 1GB

Intro

Compare those specs to the Radeon HD 6750 1GB, which comes with a clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also uses a 128-bit memory bus, and makes use of a 40 nm design. It features 720 SPUs, 36 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4670 512MB		70 Watts
Radeon HD 6750 1GB		86 Watts
	Difference: 16 Watts (23%)

Memory Bandwidth

The Radeon HD 6750 1GB, in theory, should be quite a bit faster than the Radeon HD 4670 512MB in general. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 4670 512MB		32000 MB/sec
	Difference: 32000 (100%)

Texel Rate

The Radeon HD 6750 1GB is just a bit (more or less 9%) more effective at anisotropic filtering than the Radeon HD 4670 512MB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 4670 512MB		24000 Mtexels/sec
	Difference: 2100 (9%)

Pixel Rate

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

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 4670 512MB		6000 Mpixels/sec
	Difference: 5600 (93%)

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 (in units of MB per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the interface width by its memory speed. If the card has DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the video 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 card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the core clock speed. 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 fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.