Intel server adapter pro

Hi,

1.        I have a Intel®  PRO/1000 PT Quad Port Server Adapter.

• Can i install this in a PCIE*1 slot ?
• will there be any degradation in the performance.
• can we use  Intel Gigabit ET Dual-Port Server Adapter in absence of   Intel®  PRO/1000 PT Quad Port Server Adapter.? what is the difference.