iMac Early 2009 24-Inch Northbridge Running Hot
My iMac Early 2009 24-Inch computer's Northbridge Die and Heatsink are running hot. The fans come on and go full blast. This started a week ago and occurred only one time. Now it is any time I use the computer.
The newest symptom is the screens flickering. I had another monitor hooked up to the iMac. I since disconnected it because the flickering was so bad. Then the iMac screen started flickering late yesterday.
I'm running iStat to monitor the fluctuations in the temperature.
Current temperatures with fans running full blast (in F degrees):
Northbridge Die 159
Northbridge Heatsink 149
Northbridge Proximity 137
Could it be my Logic Board and/or the Graphic Card going bad?
Thank you.
iMac, OS X El Capitan (10.11.6), 8GB RAM, Glyph 3TB Ex. HD