Thanks for the info, the computer I put together wouldn't switch on at first, then I took the mobo out and put it next to the case, but still connected. It switched on. I screwed it back in, would constantly cut out and come back on.
Thought it was the mobo, swapped it for another one, same problem. Swapped the psu and it's been stable ever since.
Now got the psu I RMAd back and have yet to put it into a new PC.