GeForce 8600 GT 256MB GDDR3 vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which comes with a GPU core clock speed of 900 MHz, and 2048 MB of DDR3 RAM running 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 8600 GT 256MB GDDR3		47 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 18 Watts (38%)

Memory Bandwidth

Theoretically speaking, the GeForce GT 640 DDR3 should be a lot faster than the GeForce 8600 GT 256MB GDDR3 in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 8600 GT 256MB GDDR3		22400 MB/sec
	Difference: 34624 (155%)

Texel Rate

The GeForce GT 640 DDR3 should be quite a bit (about 233%) faster with regards to AF than the GeForce 8600 GT 256MB GDDR3. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 8600 GT 256MB GDDR3		8640 Mtexels/sec
	Difference: 20160 (233%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce GT 640 DDR3 is superior to the GeForce 8600 GT 256MB GDDR3, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 8600 GT 256MB 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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transported past the external memory interface in a second. The number is calculated by multiplying the bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. 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 can be processed per second. This is worked out by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines 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 fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.