4 Port USB 2.0 PCI Card & PCI Express x1

I just bought a new HP Pavilion a6720y Desktop PC. I have 2 USB 2.0 PCI cards (4 port hubs) from my retired Gatway PC which I would like to use in the HP. The HP has 3 PCI Express x1 slots. Will the PCI cards work in the HP or am I stuck replacing them at $45.00 each? From reading some of the Q&A with alot of terms I am not familure with I think the answer is yes/maybe. So in my own words is the switch compatable, is there any loss in speed or proper function, is there a need to cover the rest of the card contacts so the don't touch the motherboard.

Thanks, Rick

Thanks Andrew. I opened up my HP and saw that they would not fit. So I ordered Express X1 USB Hub and it worked as it should.