GeForce GT 640 DDR3 vs Radeon HD 6750 1GB

Intro

Compare those specs to the Radeon HD 6750 1GB, which comes with core 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 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

Theoretically, the Radeon HD 6750 1GB should perform a small bit faster than the GeForce GT 640 DDR3 overall. (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%) better at 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

The GeForce GT 640 DDR3 is much (about 24%) better at FSAA than the Radeon HD 6750 1GB, and should be able to handle higher resolutions without slowing down too much. (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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transferred across the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 once 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, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.