GeForce GT 640 1GB DDR3 is a fast middle-class GPU part of the GeForce 600 Series released by NVIDIA in 2012.
It's based on the Kepler GK107 architecture and therefore not related to any of the 500 Series GPUs.
The Kepler architecture allows more Pipelines but the Fermi Pipelines (used on the 400 & 500 Series) are clocked twice as fast as the Kepler architecture. Therefore, don't let the large amount of Pipelines fool you, as the 384 Pipelines are equivalent to 192 Pipelines, of the Fermi architecture.
The memory bandwidth is its greatest hindrance. A 2GB version is also available but there will be no benefit in buying one, since the maximum amount of memory this GPU can process is actually less than 1GB.
The Result is a pretty solid GPU, with a memory bottleneck that should be able to play very demanding games like Metro 2033 at medium or high settings, while less demanding games will run on the highest settings.
Source [Pip]
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