single 240mm rad or add a 120 too?

[Mercutio]

Just curious, what's the tradeoff here. Have space for a 240mm on the roof of my case (even room for a push/pull there if wanted) but also space for a 120mm rad on the usual exhaust on the back and/or 1 on the side.

Would more rads be better or does it depend on other things like tubing size and flow? I'd guess a high flow single radiator setup might beat multiple radiators but i'm curious

 

[The Asgard]

I use a 360 and 120 with the gear below. In the desktop I run passive while gaming the 360 is brought into the equation. Pretty much silent. The only issue is reduced flow so you do need a decent pump, I use a D5.

 

[eddyr]

I suspect you'd be fine with a 240.

I had my quad and 5850 under water on a pa120.3 with a 10w ddc, (I have relativly low restriction blocks although a nice 90degree bend to get into the rad), even on lowest fan speed it more than handled the heat from both oced (cpu @3500 and gpu@950).
Just a little too much to handle passivley but kept both at safe, if a little high, temps while gaming.

edit: while passive I mean. tubing and bocks would get hot to the touch.