GeForce 9600 GT 512MB vs GeForce GT 640 DDR3

Intro

Compare those specs to the GeForce GT 640 DDR3, which comes with a core clock frequency of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also features a 128-bit memory bus, and uses a 28 nm design. It is comprised of 384 SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce 9600 GT 512MB		95 Watts
	Difference: 30 Watts (46%)

Memory Bandwidth

As far as performance goes, the GeForce 9600 GT 512MB should theoretically be just a bit superior to the GeForce GT 640 DDR3 overall. (explain)

GeForce 9600 GT 512MB		57600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 576 (1%)

Texel Rate

The GeForce GT 640 DDR3 is a lot (more or less 38%) better at AF than the GeForce 9600 GT 512MB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 9600 GT 512MB		20800 Mtexels/sec
	Difference: 8000 (38%)

Pixel Rate

The GeForce GT 640 DDR3 will be quite a bit (approximately 38%) more effective at anti-aliasing than the GeForce 9600 GT 512MB, and also will be capable of handling higher resolutions while still performing well. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 9600 GT 512MB		10400 Mpixels/sec
	Difference: 4000 (38%)

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: Bandwidth is the maximum amount of information (counted in MB per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.