ran into a very informative article on the up and coming PCI-E 3.0 tech. in short, a 16x slot will have a total of 32GB/s bandwidth with a total of 1GB/s bandwidth in each direction for a single lane. probably nothing too exciting for gamers unless you want to run SLI/Crossfire, but its great news for anyone running CUDA or Fusion based apps on a workstation.
See the struggle of the faithless lot as they negate their time
How low to sink to the depths of their frame of mind