spacded you forgot one major thing about PCIe the bandwidth is not shared the same way as in PCI, so there is far less congestion on the bus and it also run in Both Directions and has much greater bandwidth than basic PCI.
But there are pros and cons to this PCIe so unless your a hard core game then move to PCIe is kind of a waste of time unless your getting a new system.
And PCIe Architecture is way a head it time in fact most of the part on motherboard are still base on LEGACY Architecture dating back to 80's so in the real world you only see marginal performance increase depend on what you doing with it.
YUP vapourware bitboys ring and any bells hehehehe.