It is true that both Georgia and Tennessee are not current members of the Drivers License Compact that requires members to trade information regarding moving violation convictions back to a driver's home licensing state. However, both TN and GA have made agreements with other states to share information regarding tickets their drivers have received out of state.
We have not been able to find a list of what states TN has reciprocal agreements regarding exchanging of driver's out of state traffic violations. To find out if TN does have an agreement with Georgia to share this information back and forth, check with the Tennessee Department of Safety. They should also be able to tell you if the Georgia ticket will go on your TN driving record and if any points will be assigned. In Tennessee 12 mph over the speed limit is a 3 point offense.