In a direct answer, most metals have a memory and an ideal crystal structure. This structure gets distorted through the extruding of the metal to make the wires and most significantly through the heating of the solder process, which is why I always design to have as few solder joints in the signal path as possible. Running a signal through the wire and joint slowly restores it back to its original structure although slowly. Cryo causes the crystal structure to "relax" and spring back quicker. While I do use metals in the GE, the carbon fiber and Graphene would be unaffected by the cryogenic process - other than to make the Graphene a virtually perfect conductor when frozen. So how many of your wives would put up with you having a tank of liquid Nitrogen in your living room? Yah...Exactly. You though the liquid Nitrogen was cold...
Bob