Originally Posted by bombastinator
well, you do, it;s just not fanned. There's all that bottom and side space. You could also swicth to a 120mm radiator and hang it in the rear hole unless you already bought your 240.
As a side note I tried to figure out how little radiator you could get away with in a massively unscientific fashion:
The 780s will draw what? 350w each? Then there's the cpu, call it 100 just to be safe? That's 850w. total. Call it a bit under 2800 btus. Now your smallest room air conditioner is good for 5000 btus and has an aluminum radiator not one hell of a lot bigger than your 340. xspc is not listing the radiant capacity of their radiators, but we do know it's copper, which is 20% better than aluminum.
The GTX 780's are 250w each, not 350w.
My wife's rig is a 2700K OC'd to 4.7GHz with a pair for GTX 560Ti's (210w each before the overclocking) and she is running nice and cool with just a singled 45mm RS360 radiator and a 45mm RS120 radiator. Her computer and my beast (3770K OC'd to 4.8GHz with 2 GTX 580's that are also OC'd) are both in our office and with the normal house AC unit, the room is very cool.
Going off some basic assumptions, say an Intel 4770K OC'd to 4.5GHz @ 1.4v, 2 GTX 780s, 1 HDD, 8 high performance fans, 4 USB devices, a D5 pump, etc. Even at 100% TDP load (which is only done during Folding@Home or stress tests, the total wattage is 718W and they recommend a 768W power supply. At a more "reasonable" 90% load, it's 707W draw and a 757W power supply.
So plug in your handy dandy wattage to Btus converter, and at 100% load, you are talking only 2451 BTU's.
So your notion of going to a 360+120 radiator isn't a bad idea. That's basically what my wife's rig is.
Me on the otherhand, I'm insane. I have an RX360 (60mm thick radiator) and an Alphacool 360 (80mm thick radiator) and 12 1450RPM fans in "push/pull" mode) ... so that rig isn't the best example, and I built is for serious 24/7/365 overclocked Fold@Home work.