£99.95
http://www.overclockers.co.uk/showproduct.php?prodid=CA-010-XI&groupid=701&catid=123&subcat=2466
I've not tried passive before, I didn't realise how much noise the PSU made until I made the rest of my PC so quiet, my old PSU was only 500w too so it was working quite hard to power the 7970 and 3770k. This one is more efficient too.
Really happy with it.
Those fans are a bit odd.