Originally Posted by Anoxy
I am so new to watercooling I don't even know the difference between those two haha.... but I'm assuming multiple closed loop coolers is what oshu
posted above? And a custom single loop would be like one radiator that has hoses running to both GPUs and my CPU?
You got 99% of that correct.
Closed loop coolers are just another name for the pre-made Cosair or whoevers units. Named so, I believe for the fact they are sealed all in one units.
Also you can have multiple radiators in a single custom loop. The single denotes that everything you want to water cool such as CPU, GPU, RAM, chipset/VRM share the same radiator(s), pump(s), reservoir so everything is contained within a 'single loop'.
Multi loop is just taking components and cooling them independently with it's own set of pump(s), reservoir, radiator(s). A popular choice is CPU and motherboard on one loop and video cards on another. Custom just means spec it and build it yourself from individual components.
Hopefully that was clear enough to understand the basics.