So looks like I may have to bite the bullet and get a new psu.
With it being a living room PC I would prefer one were the fans only spin under load , looking at a hx750i which meets Bagley's platinum recommendation and also only spins up on load.
Anyone have experience with this psu.
I have the 850 version. It's a great PSU. Only thing the reviews seemed to mention at the time - correctly - was that the cheapish cables that come with it can be a pain to get "latched" correctly. Push them in REAL HARD and make sure they are fully latched and you should be fine.