Tim:
Re the "not overheating" are you judging by sensor readings, or have you felt the card to see if it's hot?
Jon LaBadie:
from sensor readings via the nvidia-settings program. Once I suspected the video card I logged the output at 20 min intervals hoping to see the temps rise. Typically running in the low 30's (C) and reaching a max of 44 degrees. Fan speed ranged from 1200-1320 rpm.
It might well be worth opening it up and inspecting it. You could just have a heatsinking problem (dried out compound, not firmly attached, clogged fins).