Passive though meaning no pump or fan. I'm still not sure Raijintek's passive water cooler can handle up to the rumored 200 watts of heat. Maybe it is possible?
If the top of the case is fully vented and this is placed up there, there could be enough normal air convection, as long as the case also has good fresh air source to let it work.
Most of the "fanless" stuff has fine print of optimal placement and air flow via case fans.
It's easy to move a decent amount of air w/o producing enough noise pressure to notice without being a few inches away.
biffzinker is right. Fully passive, so also not cheating and relying on case ventilation, it is not possible.
A quick calculation with an online calculator, http://www.thermal-wizard.com/tmwiz/con ... p-isot.htm
, and data from a table on, http://www.xtremesystems.org/forums/sho ... Efficiency
, (from Martin I think) gives a max of 85 watts of heat transfer.
I am gonna see with my own AIO cooler(CM Seidon 240V, which is very much recommended by me) what temps are gonna be with applied load. Stressed and monitored with AIDA64.