GeForce GT 640 DDR3 vs Radeon HD 6750

Intro

Compare that to the Radeon HD 6750, which comes with GPU clock speed of 725 MHz, and 512 MB of GDDR5 memory set to run at 1000 MHz through a 128-bit bus. It also is comprised of 720 Stream Processors, 36 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

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

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

Texel Rate

The GeForce GT 640 DDR3 should be a bit (more or less 10%) better at AF than the Radeon HD 6750. (explain)

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

Pixel Rate

If using a high resolution is important to you, then the GeForce GT 640 DDR3 is superior to the Radeon HD 6750, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 6750		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: Memory bandwidth is the largest amount of data (in units of MB per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the bus width by the speed of its memory. If it uses DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster 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 applied per second. This figure is calculated by multiplying the total texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to 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 ability to get to the max fill rate.