Fixed. I had to tweak the shield a little to get it to line up with the mobo i/o's. I remember now that my case has a glitch and when I installed my P4P800 a couple years ago it was the same. Taller SO's would not fix it as the PCI cards would not line up then.
Not to hijack this thread, but by "i/o shield", you're referring to that little tinfoil cutout that clicks into the back of the case? Where all the USB/network/etc stuff comes out? That little thing handles grounding duties for peripherals? I always thought those plugs would be grounded to the motherboard proper?
i7 2600K | ASUS Maximus IV GENE-Z | GTX Titan | Corsair DDR3-2133
"The metal fins on the I/O shield ground the I/O connectors to the case and they will offer some resistance to the mainboard when it is placed. This is natural. Just manipulate and push the mainboard toward the I/O shield until the I/O device connectors protrude and the mainboard holes line up with the case standoffs."