After quite a bit of deliberation, I convinced myself to go ahead and try the Corsair 540. I wasn't able to find much information or examples of quiet builds for this machine, in fact quite the opposite, most youtube builds etc seemed to almost ignore acoustic properties entirely. The airflow design and compartmentilization was just too enticing for me and I went for it.
Some background for my personal use of this machine. This is my home PC in my office, I game on it, email, standard everyday productivity stuff, nothing very intense.
Intel 4790k on an Asus Z97 board
Asus Strix 950 OC Edition
EVGA Eco Series 650 Watt
Seagate HD ( dont remember the spec, but its not anything fancy )
Noctua CPU Heatsink and Fan
One case fan swapped out to a Noctua 140mm
I obviously also have memory and a SSD in there etc.
The Video card, power supply, and fans were all chosen according to there acoustical performance.
The Asus 950 will run with its fans completely off, which in my case is almost all the time. In fact I have never heard the Video card make a peep.
The EVGA power supply also runs in a fanless mode, the fan does run intermittently, however it is practically in-audible. I believe it is advertised to have a maximum of 20db-ish under load.
The Noctua heatsink and fan are a fantastic addition to this build, it is the only fan that runs 100% of the time. Even through the open "airiness" ( is that a word ), multiple ventilation grills of this case, you can't hear the thing without intent focus.
The Corsair 540 comes with 3 140mm fans. I can't speak for everyone's experience with these fans obviously, but in my opinion, they are total garbage. They work and they move a good amount of air, but they had a "grindy" quality of sound to them, especially at low speeds. I quickly realized that I was going to have to do something. Popped in a 4 pin PWM Noctua fan as a replacement, exchanging out the bottom of the two intake fans mounted at the front of the case.
Using the onboard fan control offered by Asus, which in my opinion has been excellent; I have been able to tie all the fans to the CPU temp. The CPU heatsink itself follows a default curve. The Noctua case fan(the one that I replaced, intake) located at the bottom/front of the case remains off until 37C is reached, and then follows a basic curve. After quite a bit of tinkering, the second and third case fan do not fire up until reaching 60C on the CPU. So far the inherent cooling ability of this case has really offered great thermals, and I've found that the cpu cooler and that one Noctua case fan can keep the CPU temp between 35C and roughly 58C for like 95% of my activities. * When those two Corsair fans do turn though, boy do you know it, completely ruining the almost in-audible system overall. Like I said before, they almost never turn on, and this being a new build, if I find in the future that they begin to bother me, I will simply change them out to some higher quality fans, but for now, I just don't see the need.
The Seagate HD....this was the outlier. Long story short, this thing was creating a "humming", and without going into the details, it simply needed to been better secured. The Corsair 540 comes with two "hot swap" style 3.5" bays, it was my experience that they may not secure the drives quite up to everyones standards. This was a fairly easy fix.
Overall, the things that really stand out in my mind as the key players keeping this build quiet are those Noctua fans that Asus MB. The fan control on the MB was really all that you could ask for, able to tie temp thresholds to one of many temps, completely customize the fan curve however you wanted, and all very easy to do, no guessing or tinkering in Speedfan.
This has probably been discussed a ton here in these forums already, but getting first hand experience with the 4790k has been nothing short of epic. I was totally prepared to go through a rigorous undervolting process to really keep those temps down and I was completely blown away. I still haven't determined if its the chip itself, or a combination of the MB control and the chip; but the voltage control and the core clock throttling are just simply amazing. I came from an A10-5800k, and it would throttle down when not in heavy use, but it would throttle down in like one big step, from 3.8 Ghz to like 900Mhz or something like that, all the while holding steady at the same voltage( which I had undervolted quite a bit ). This Asus MB and Intel's 4790k Seems to almost be constantly throttling up and down between 800Mhz and the 4.4Ghz cap at various increments, same thing with the voltage, all the way from 1.2ish when its on turbo, down to .7! Anyway, I wasn't ready for it and had no idea intels chips were like that, and like I said, the experience in general has totally knocked my socks off. In short, bye bye AMD...lol.
I don't have a db meter, but after building at least 40-50 machines through the years, this thing is quiet. After a few weeks of use, it seems as though the heaviest task I load on the machine are the late stages of a multiplayer Civ 5 Game with friends as the host. Hosting a huge map with 8 players, 20 city-states, and barbarians all over the place loads up a CPU like no other game I've seen. This thing chews through it like butter almost never breaching the 60C thresh hold on the fans.
Don't have any pics, guess I should, but we've all seen enough pics I would think. If I get around to taking some, I will post em up.
But Anyway, It can be Done!!