[davidzo]

Its probably not the flowrate. even with a super-low flowrate the results can be quite ok. you won't get the best performance with an outdated pump, but if it is still moving the water it won't let your pc get so hot.

Because the idletemp is quite ok it can't be the pump because it has a constant flowrate. The idletemps would be worse if it was only the pump.
I think its obvious that it is the Radiator and maybe the cpublock too. The Reserator simply has not enough power to cool the cpu, northbridge and two graphics cards. A single black ice pro with an pabst supersilentfan would be more powerful than this passive Radiator. Second thing is the waterblock. Zalman uses a really old blockdesign similar to an old Innovatek Rev.3 but a little smaller. There is at least 5mm of copper between the water and the DIE, which isolates and is'nt good for the heat transfer.
The Radiator and the Waterblock are the most important components in a rig like this. The pump can theoretically give some extradegrees, but when the radiator is so hot like here a larger and better pump would even perform worse because it produces more heat that the Radiator can't handle. A block like the zalman is a laminar flow block which doesn't scale with added flow. A watercooling rig is alwas as good as the worst part of it...


EDIT: I see that this guy used a parallel way of flow to otimise flow. In most cases a parallel waterflow is wors than a serial one because of different pressures. Maybe his cpu doesn't get enough waterflow because most water is going trough the graphics card cooler. it can be that he gets this low idletemps because its an A64 with cool n quiet.