Thanks for the feedback, that's good info to know. I was actually considering trying that board with an old Pentium D CPU I have lying around since it wouldn't work with my E5300, but looked more at the P45X3 since it has more 1x slots if I ever wanted to add several GPUs. Gonna have to do some digging to see how similar these boards are as far as chipset and bios.
EDIT: This is the board I am looking at:
http://3btech.net/asp4coqu16mo.htmlMore 1x slots is great to have. I see one big difference in the P45X3 from my board: it has a proper 8-pin power connector. The board I have has the same molex from the back of an IDE CD-ROM drive. It's quite possible my board wont see these cards because of bus power from PCIe. Plus, the P45X3 specifically says PCIe 2.0, which is probably the other problem with my board being PCIe 1.0.
I'd be surprised if the P45X3 didn't work. I may just order one to test it.