I just read the article about PCIE x16 slots that are revision 1.1 being backwards compatible with revision 2. How would one figure out what PCIE x16 slot revision he has?
You read the chipset manuals... if available.
For Intel chips any manual is available.
AMD and nVidia are not that nice. AMD is always late and nVidia has several products based on the same chip, but you can't be sure, because of the companion chips, for example 680i with PCIe 2.0 chip. In fact, it does not really matter if you have 1.0a, 1.1 or 2.0 ... some games do speed-up when levels are loading, but while running the effect is quite small. PCIe 2.0 is backwards compatible down to 1.0a.
So changing the board for PCIe 2.0 does not make sense... if you want to use a quad-core, it would be good, because the VRM on your board is quite weak and extremly cheap.