GeForce GT 640 DDR3 vs Radeon HD 6750 1GB

Intro

Compare all that to the Radeon HD 6750 1GB, which comes with core clock speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 720 SPUs along with 36 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 6750 1GB		86 Watts
	Difference: 21 Watts (32%)

Memory Bandwidth

In theory, the Radeon HD 6750 1GB should perform a small bit faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 6750 1GB		64000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 6976 (12%)

Texel Rate

The GeForce GT 640 DDR3 should be a bit (about 10%) faster with regards to anisotropic filtering than the Radeon HD 6750 1GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 6750 1GB		26100 Mtexels/sec
	Difference: 2700 (10%)

Pixel Rate

If using high levels of AA is important to you, then the GeForce GT 640 DDR3 is the winner, by a large margin. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 6750 1GB		11600 Mpixels/sec
	Difference: 2800 (24%)

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 max amount of data (in units of MB per second) that can be moved over the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 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 number of texture map elements (texels) that can be applied 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 card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. 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 also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.