Lo again I just recently got loads of kit for my box, in an attempt to shut it up when I am sleeping. Now my Nexus controller lets me turn off my 120mm intake and pci slot exhaust fans, and set the TT Smartfan 2 that is on my sk-7 to minimun rpm. The only thing making a noise at that point is my HiPower 420W PSU. Now, this PSU has an intake fan at the bottom and a normal exhaust fan, and these can be set to hi, low or temperature controlled, all still being noisy. I was thinking about modding it, removing the bottom intake, replacing the exhaust with another controllable fan and venting it to my top 5" bay like this: http://www.silentpcreview.com/files/images/dualie/psu_intake.jpg But before I void my warranty, I found that if I slowly move the fan speed swtich on the PSU so that it is halfway between 2 settings, both the fans turn off, making it silent. I take it there is a danger of my PSU overheating and popping if I leave it like that for too long, but I am hoping it might not be the case if my machine is just sitting downloading overnight. Can anyone give any insight? Is it best to mod it til I can afford a nicer quieter psu? cheers :)

The last thing I'd ever mess with is the PS cooling! You are asking for trouble that is more than just voiding your warantee.

There are some power supplies that have temperature controlled fans. I have worked on a computer that had the power supply fan connected to a motherboard speed controller. As an alternative maybe you can find a quieter fan of the same air flow rating.

Your psu will fail if you completely turn off its fans. It may not happen immediately but it is sure to happen. The fortron 300W and 350w are the best values among the quiet psus. http://www.newegg.com/app/viewProduct.asp?description=17-104-976&depa=0 If you do not want to get a new psu I would try turning off the interior psu fan and running the rear exhaust psu fan on low.

Cheers ppl I dunno if 350W is enough for my system/the sytem I will be getting, and I plan on getting an antec truepower then anyways. Thanks for the info, I'll mod it then, single fan who's speed I can control properly.

Here is a review of quiet psus. http://www.silentpcreview.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=28&page=1