I wouldn't worry about it. 50*C isn't all that high for a computer component. What are you doing when it reaches 90*C? The overclock most likely has a lot to do with it. When you start increasing the voltages on different components or on things like vtt it has an effect on other components. If you have your overclocked settings saved in the bios I would reset to default and see if it makes a difference. If it does then at least you know why it's happening. If it doesn't then you haven't lost anything. You might try taking the side off the case for a better airflow just to see if that bring the temps down. If so then maybe some more/better/higher CFM fans are in order.