Intersect Overload Cartridge is a device created by the CIA which is designed to destroy the Intersect 2.0 computer and cube if something was to go wrong, rather than letting the Intersect wind up in the hands of their enemies such as Fulcrum and The Ring.
Rather than destroying the Intersect cube and computer by explosive means this device, when inserted into the computer terminal floppy drive, generates a massive power surge that burned out the Intersect Cube. The surge spread to the monitor (and cracked it) as well as the walls of the chamber.
This device was in possession of Bryce Larkin in "Chuck Versus the Ring"; the CIA's choice for the new Intersect 2.0 Human Intersect, who carried it around in a metal box, ready to be used if anything went wrong. When Bryce was mortally wounded in the ensuing gun fight that followed the Ring agents infiltrating the Intersect Base, he asks Chuck to use the device as the Intersect to prevent the Intersect from falling into The Ring's hands, before dying from his injuries. Chuck approaches the Intersect terminal but decides to upload the Intersect 2.0 to himself before destroying the computer system.
The efficiency of the device could be brought into question as Manoosh Depak has managed to reverse engineer the destroyed components of Intersect 2.0 computer, using them to create his Intersect Glasses.