GeForce 9600 GSO 768MB vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which features a clock frequency of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also uses a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 384 SPUs, 32 TAUs, 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 9600 GSO 768MB		84 Watts
	Difference: 19 Watts (29%)

Memory Bandwidth

The GeForce GT 640 DDR3, in theory, should be quite a bit faster than the GeForce 9600 GSO 768MB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 9600 GSO 768MB		38400 MB/sec
	Difference: 18624 (49%)

Texel Rate

The GeForce GT 640 DDR3 is a little bit (approximately 9%) faster with regards to AF than the GeForce 9600 GSO 768MB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 9600 GSO 768MB		26400 Mtexels/sec
	Difference: 2400 (9%)

Pixel Rate

If using 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 9600 GSO 768MB		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 information (counted in megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total amount of texture units by the core 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 per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.