Watercooling question

[Canada's Own Falcon]

Hey guys, a little new to water cooling, I've done some in the past, but I'm looking at setting up a new comp, and wanted to ask a quick question first.
I'm going to be running dual 4870's in crossfire, and will be overclocking the system, I'll be running a 3 fan rad and a pretty good pump (swiftech mcp655 1200L/h).
I'll be using watercooling to cool the entire system (ram/hdd aside) and want to know what would be more eficient, the 2 scenarios below.

1 pump going cpu, top card bottom card, northbridge rad.

or

2 pumps running paralell (sort of)
first pump going CPU, northbridge T-bracket-Radiator
Second pump - Top card, bottom card T-bracket-rad


I figure the second one would provide better temps on the gfx cards, but will the Tbrackets before the radiator become too much of a bottleneck. It will of course have a Tbracket before and after the rad to split the 2 loops and pumps.

[Spawn-Inc]

never split a loop, you ALWAYS want things in sereis.

i would go with 2 loops for what you want to cool.

1st loop
Res/T-line > pump > CPU/RAD/Northbridge > CPU/RAD/Northbridge > CPU/RAD/Northbridge > Res/T-line

2nd loop
Res/T-line > pump > GPU1/GPU2/Rad > GPU1/GPU2/Rad > GPU1/GPU2/Rad > Res/T-line

the only order that matters is that the Res/T-line is before the pump, everything else should be connected for the shortest loop possible.

i would go with at least a double 120mm rad for the cpu and n/b and a triple 120mm rad for the GPU's.