The SR-2 Classified motherboard supports the function of disabling the PCIe slots instead of removing a card for testing purposes.  The jumpers to disable the slots are located above the 24 pin power connector.  They are all default enabled,  To disable a specific card move the jumper for that card to the right position.    If you have a EVGA Control Panel (ECP) it will have this option.  ONLY MOVE THE JUMPERS WHEN THE SYSTEM IS OFF.