I've read a few articles in the forum about this topic so thought I'd throw in my experiences, hopefully this may help someone else. The following is my set-up with a 900D. It could be argued that a 900D and AX1200i is overkill in my situation but to be honest, both will be with me for years and I've no doubt I'll rebuild many times before I've finished. Gamers would say I'm bonkers and should have a full watercooled loop and nice indoor lighting. Nah !!!!
To get temperature absolutes you would need a hermetically sealed case, apart from the fan ports. Such a beast doesn't exist as far as I'm aware so I leave discussions on temperature coefficients to the ones with more experience. Discussions on Push/Pull/Exhaust drove me crazy as there doesn't seem to be a definitive answer. My solution maintains Positive pressure, or so I beleve.
The parts generating most heat are as follows:
MB:Asus P9X79-E WS
CPU:Intel Core i7 Extreme 4930K 3.4GHz
PCU:NVIDIA Quadro K4000
Mem:Dominator Quad Channel 2133 DDR3 [16Gb]
All fans are Noctua [NF-S12a and NF-A14]. They are very quiet indeed.
CPU Watercooled [Corsair H110]
Main Apps are Prem Pro CC and Photoshop/Lightroom, basically digital imaging.
I hope someone finds this useful.