Thanks for this guide... I want to water cool my rig. The components I want to water cool are fallowing: i5 2500 K over clocked to 4.6 GHZ x2 MSI 680 Lightening at stock. May want to over clock it very little if any for benchmark purpose. I would like to create a custom loop... I did some planning in attached image that presents components I want to use and direction of air flow and water circulation. I spent hours jumping from forum to forum and discovered that general rule of thumb is 120mm radiator per component and 240mm for overclocked component in my case that would be: 240 CPU +240 GPUs = 480 mm of radiator in total Now why is my diagram presenting a total of 440 mm that is because I read a 240 radiator with high pressure fans that I want to use would perform just as good as the 280mm Rad. and that is why. Also I believe just like with PSU calculator I consider that my components will never at once be 100 % Load and go with 90 % utilization instead.(Seams like everyone have its own theory on this) Following is a list of components I want to use with links: XSPC Raystorm EX240 Universal OR XSPC Raystorm 750 EX240 Extreme Universal Phobya Xtreme 200mm Radiator x2 EK MSI GeForce 680 GTX Lightning VGA Liquid x2 Corsair Air Series SP120 Corsair Air Series AF140 Quiet Edition x2 200 mm stock Corsair Air from 650D case I'm seeking your expertise . I feel like I need more radiator power but I'm getting a new case and I don't want to hard mod this one. Your input will decide if I will move on with this project or stay on air until next time... The main reason why I want to go water is a challenge that comes with this project...Thanks.