NVIDIA GeForce GT 640 review roundup: a $99 card that fails to keep Kepler's promise
 

NVIDIA blew reviewers away with its flagship GTX 680, but building cards for the low-end is a whole different challenge. The GT 640 hits the $99 price point, where it sits right between the AMD Radeon HD 7750 at $109 and the last-gen Radeon 6670 at around $80. As it turns out, these rivals pull off something of a pincer movement, leaving NVIDIA's card little room to retaliate. The GT 640 contains a 28nm Kepler chip, but it's a cutdown version of the silicon with just 384 CUDA cores, a poor memory bandwidth of 28.5GB/s and no GPU Boost feature -- which means the card can't boost its 900MHz to make use of thermal headroom. These limitations have a significant impact on the benchmarks, as you'll see in our little review roundup after the break.

http://www.engadget.com/2012/06/20/n...eview-roundup/