I've been pursuing a silent gaming build since forever. My last build with 3570k and 980ti in a Fractal R5 could be called somewhat quiet and serves as great learning experience for this build. I live in a tropical country so the summer is pretty brutal on gaming. Ambient temperatures can go up to 38°C, making building a completely silent rig on air quite a task since the fan always have to ramp up to cope with the heat. The Fractal R5 was a great case, but the sealed nature of the case makes the GPU run hot, and high overclock with air cooler are pretty much impossible.
As the old rig got problem booting up, I took the chance to upgrade to a new system, with 1440p gaming at high refresh rate and silence in mind. Good streaming/video encoding capabilities are just the icing on the cake.
My rig is running a 4.0ghz overclock, the rig is whisper-quiet (you can actually hear my cat's tongue moving around rather than the sound of the fans/gpu). I had two overclocking profiles saved on the mainboard, 4.0ghz for the summer when ambient temperature is around 34-38°C, and 4.4ghz for other seasons.
Currently gaming on the PG279Q and the Dell U3415W, the former is used for FPS/Competitive games while the ultrawide is for RPG/Strategies game. Two monitor arms allow the two monitors to switch position with each other for optimal viewing angle (and less neck strain looking up). I do plan to cherry pick a PG348Q with minimal backlight bleed later on. Finally, cat improves your gaming effiency by 150% so you should get one yourself!
Intel i7 6800k: The cheapest 6-core offered by Intel. For the best gaming experience, I've decided to never go SLI so I don't need the extra PCI lanes of the 6850k. I chose Intel over Ryzen for the slightly higher IPC which might help squeezing out some fps for the high refresh rates.
Gigabyte GA-X99-Designare EX: I originally build this computer with an Asus Strix x99, but the mobo died, killing my previous 6800k with it so I got a refund and went with the Gigabyte. The Giga is loaded with features, strong vrms for overclocking, PLX chip for additional PCI lanes, thunderbolt, all metal-cladded ram/pci slots. Plus the color theme is more pleasant to my eyes than the traditional "gaming" color of gigabyte (white/red and orange). Only bad thing I can say about this mainboard is that the bundled softwares are crap, it's better not using them.
NZXT Kraken X52: I'm a big fan of air cooling, however achieving a 4.4ghz clock with my old Noctua D15s is pretty much impossible so I went with an AIO. Had both the x52 and the x62, with the X62 in my case, I have to sacrifice two HDD slot so I went with the X52.
My ears are quite sentitive (cats' ear haha) so I can here the pump noise even at its minimal speed. However it's not very intrusive (well a tad bit when you're listening to music in the middle of the night). The fan included are decent, not very noisy but not quite good so I replace them with 2x Bequiet Silent Wings 3.
Corsair Dominator Platinum: Not much to say here - looks good and fit my build. 8 sticks so I can make a Ramdisk for my browsing need.
Asus 1080ti Strix Gaming: I am particular about my VGAs. I need 2 HDMIs port (one for the 5.1 speaker receiver, one to connect directly to 4k TV to bypass any processing/input lag of said receiver) so the choice narrows down to Gigabyte, MSI and Asus. Silent is my top most priority, and MSI always delivers on this aspect, Gigabyte is meh, and their new "falcon"/Aorus branding is atrocious. After listening to a few sound samples of the MSI and Asus, I decided to try the Asus, thinking I could always sell it and get the MSI if it doesn't work out.
The Asus in its stock form is ... loud, since the target temperature is 69°C and the fan curves are very aggressive. I set mine to constant 40% fan speed and it is very quiet. You can only here the fan late at night when things quiet down. Setting the fan to 40% resulting in 79°C load temp for my GPU but I'd gladly take it for the silence.
Other things to note is that the VGA has 4 pin RGB header on it, so I connect my led strip to the VGA, use Asus Aura and ditched the crappy Gigabyte RGB software.
Card is quite heavy and will sag, I had a (stealthy) vga support if you look hard enough
Phanteks Enthoo Evolv ATX Glass ATX Mid Tower: still the best looking case in my opinion, went with Galaxy Silver since I like the contrast between silver aluminum and black glass, and black cat. However the case is not very big and as mentioned above, if you install a 280+ radiator in front, you will have nowhere to put your HDDs (you can stash them near the PSU, but they VIBRATESSSSSSSS). The frame is not as rigrid/strong as my old Fractal R5, but it's solid enough.
The glass is smexy as ****, with just enough tint.
SeaSonic 750W 80+ Gold: fan doesn't spin even when the system is heavily OC-ed. Modular cables and Seasonic quality. I did pick the Seasonic over the Corsair RM850x dues to the cabling though. Corsair uses capacitor in their RMx/RMi series so if you plant to do PSU cable modding, they're quite clunky (you can remove the capacitor but your PSU ripples will increase slightly).
Lighting, Case Fan and Other accessories
-The case is lit up by my 4 custom-made led strip (normal 5050 RGB led, strapped on an aluminum tubes with an acrylic diffuser on top). The result is quite pleasing, soft and even light. I decided against the Hue+ Led Strip due to the amount of cable management required, and with normal led strips and Asus Aura, you can sync the case lighting to other components like Ram.
-Rear exhaust fan is NZXT AER 140, not the best fan in the world but it's quiet enough when stopped down to 600RPM, and the led is pretty.
-PSU cables are MDPX B-Magic, Platinum Grey and White.