GeForce 8800 GS vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which comes with GPU core speed of 900 MHz, and 2048 MB of DDR3 memory set to run at 1782 MHz through a 128-bit bus. It also features 384 Stream Processors, 32 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
GeForce 8800 GS		105 Watts
	Difference: 40 Watts (62%)

Memory Bandwidth

In theory, the GeForce GT 640 DDR3 should perform much faster than the GeForce 8800 GS in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 8800 GS		38400 MB/sec
	Difference: 18624 (49%)

Texel Rate

The GeForce GT 640 DDR3 is just a bit (approximately 9%) more effective at texture filtering than the GeForce 8800 GS. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 8800 GS		26400 Mtexels/sec
	Difference: 2400 (9%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GT 640 DDR3 is a better choice, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 8800 GS		6600 Mpixels/sec
	Difference: 7800 (118%)

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 max amount of data (measured in megabytes per second) that can be transported past the external memory interface in one second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 are processed per second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics 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 maximum amount of pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units 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 rate is also dependant on lots of 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.