I would say it's noticeable, but not loud
This. I literally went through at least five units with Amazon throughout that fiasco of theirs with bricked systems and such. All the systems I tried had an audible fan going. It's impossible for something that generates heat to be "whisper quiet"; the fans are gonna fuckin' spin to move the heat out.
My children are noisy...
I noticed a difference when I had mine vertical with no stand. because there are no rubber feet to dampen vibrations, I think. I put it horizontal and the noise went down appreciably.
Physically speaking (i.e. the case), I don't think the PS4 is a good design. If they were dead set on making it as small as possible (a mistake that prioritizes "gee whiz" over functionality), intake vents should be on the front of the console instead of the sides. In any normal shelf or open-front entertainment center this is the source of cool air. The exhaust is okay on the back because it will either be blown out the back of the entertainment center or on a shelf it will swirl around and rise to the top of the enclosure and escape out the front. The console sits low so the front-facing intake vents will still be pulling in cool air.
With the PS4, the intake vents seem to be along the sides, so unless you've got no back to your shelf that hot swirling air is going to circulate to a degree. This essentially forces users to a) have a backless entertainment center where all the ugly cords are hard to hide, or b) set the console out on a table or desk. That might be okay with kids and college students but it's not to me (or the wife).
So why is this noise problem considered a non issue? It seems like it's around 50/50. Some people experience the pure bliss of the most powerful system on earth being whisper quiet and others experience a disgusting loud putrid noise spewing from their once loved system. It seems like quality control is all over the place. Sure, failure rate might be below 1% but what about the noise. All the noise noise noise. For me, it's extremely annoying but I didn't want to go to the trouble of replacing it. Well when it died I had no choice. So I better get a whisper quiet PS4 or else I'm going to crack the system over my knee and throw it off a boat.
It's a lottery with the PS4, too? I remember getting unlucky and getting one of the loud as fuck ps3s. God, that thing was awful.
did you know that the PS4 also has intake vents at the back? it does
i consider it a non-issue because it seems normal to me. the fans kick in when the system is being stressed...it seems like everything is operating as it should.
On Don't Starve, really? That seems odd since it's completely digital. My PS4 only ever gets somewhat loud when I insert a disc for the first time, then it quiets down.