3x140 or more?

[Flyinfinni]

I'm considering going watercooled on the system in my sig. Would it benefit much to go with more than just a 3x140 rad or would a single 3x140 rad already be getting the water back to near ambient?

 

[Cruiza]

Not sure what your definition of "near ambient" is, but a 420 would likely cool your sig rig just fine. If you have extra room and cash and plan on OCing a lot, though, you might want to consider a bit more rad.

 

[Tsumi]

Look at my sig. I'm using a 3x140 radiator to cool a Phenom II 1090T (hotter than your 750) and two GTX 470's (much hotter than your 6850's). Temps on everything rarely peak above 65 C, with an ambient of around 20-25 C. Water temps are probably around 35-40 C.

 

[Flyinfinni]

Part of my issue is high amb temps (as high as 29-30C). The idea would be for the loop to go CPU-->GPU1-->GPU2-->Res-->Pump-->Rad. I'd like the water entering the CPU block to be as near Ambient as possible, which would require the rad to dissipate basically as much heat as the 3 components would generate so that the second GPU wouldn't get too hot. Ideally, I'd like to keep the water temp ~35C or less. Maybe I'm being unrealistic, but with such high amb temps, I need to work to keep things cool.

 

[Tsumi]

Completely depends on the fans you run, and the radiator you use. I use a GTS 420, which is a high FPI radiator, with 3 1500rpm 140mm fans. Now, this is not ideal for this radiator, high FPI requires more fans/higher speed fans. Not to mention I use this in a closed case where the design is negative pressure flow, so the radiator is not getting as much air as it would get when the case door is open. When I open the case door, my temps can literally drop an additional 5 C. I plan on adding an additional 3 140mm fans later on, most likely the Aerocool Shark 140mm. Or maybe a couple of 1850 RPM Gentle Typhoons on 120 to 140mm adapters.

If you used a lower FPI radiator, you can get away with slightly lower speed fans.