I'm fairly certain that its my old PSU. I've been using the new PSU very extensively over the past couple of days without any incident. So, now I'm deciding between two different PSUs:
Corsair TX650w
http://www.newegg.com/Product/Produc...82E16817139031
Corsair TX750w
http://www.newegg.com/Product/Produc...82E16817139030
OCZ ZT Series 750W
http://www.newegg.com/Product/Produc...82E16817341052
I'm looking for a modular PSU that has good future-readiness. Any other recommendations would be appreciated!