GeForce 8600 GT 1GB GDDR3 vs GeForce GT 640 DDR3

Intro

Compare all of that to the GeForce GT 640 DDR3, which comes with GPU clock speed of 900 MHz, and 2048 MB of DDR3 memory running at 1782 MHz through a 128-bit bus. It also is comprised of 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 8600 GT 1GB GDDR3		47 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 18 Watts (38%)

Memory Bandwidth

Theoretically speaking, the GeForce GT 640 DDR3 will be 155% faster than the GeForce 8600 GT 1GB GDDR3 overall, because of its higher bandwidth. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 8600 GT 1GB GDDR3		22400 MB/sec
	Difference: 34624 (155%)

Texel Rate

The GeForce GT 640 DDR3 should be much (about 233%) better at anisotropic filtering than the GeForce 8600 GT 1GB GDDR3. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 8600 GT 1GB GDDR3		8640 Mtexels/sec
	Difference: 20160 (233%)

Pixel Rate

If using high levels of AA is important to you, then the GeForce GT 640 DDR3 is the winner, and very much so. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 8600 GT 1GB GDDR3		4320 Mpixels/sec
	Difference: 10080 (233%)

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 largest amount of data (counted in MB per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 texture map elements (texels) that are processed in one second. This is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs 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 also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.