GeForce GT 640 DDR3 vs Radeon HD 5670

Intro

Compare those specifications to the Radeon HD 5670, which comes with a core clock frequency of 775 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 128-bit memory bus, and makes use of a 40 nm design. It features 400(80x5) SPUs, 20 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5670		61 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 4 Watts (7%)

Memory Bandwidth

In theory, the Radeon HD 5670 is 12% quicker than the GeForce GT 640 DDR3 overall, due to its higher data rate. (explain)

Radeon HD 5670		64000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 6976 (12%)

Texel Rate

The GeForce GT 640 DDR3 will be quite a bit (approximately 86%) more effective at anisotropic filtering than the Radeon HD 5670. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 5670		15500 Mtexels/sec
	Difference: 13300 (86%)

Pixel Rate

The GeForce GT 640 DDR3 will be much (more or less 132%) better at FSAA than the Radeon HD 5670, and also capable of handling higher screen resolutions better. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 5670		6200 Mpixels/sec
	Difference: 8200 (132%)

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 information (measured in megabytes per second) that can be transported across the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its 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 speed of the card. 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 lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.