65 is acceptable, is max really just 72?
for gpu, 90 is too high, esp since 550ti is not high end (high end ones tend to be hotter) i haven't seen anything hitting 80 since the 8800gt.
yes. try to improve airflow. also, you can try touching the heatsink (be careful), if it gets hot, if not then maybe it's not seated properly.
try opening the side panel also, see if it helps. if it does then you really need to improve airflow, add some fans, clear the cables
72 is not the absolute max but it is close. Some quick goggle searches show Tcase 72 degrees as max.. You should try to keep the cores below 70.
You really need to see what is the problem here. If you think it is airflow in the case then open the side and let it run that way for awhile. Does the temp improve significantly?
Just so you know I have the K model of that chip and it runs top end around 40 so 65 is pretty high.