What is the white large hose doing behind the S5? Exhausting the hot air? The stock fan on the S5 keeps it cool without any additional fans. Maybe overclocking?
Its fresh air from outside to keep the fan as low as possible for the sound. The S5 is in my livingroom with 2 delta fan. They run at about 2000rpm.
I wanted to try other Delta's also. What model(s) did you get and try? Are you using the stock fan plus another 38mm as the pull, which is a Delta? Which model? There are so many.
Even though I'm switching to Noctua's I'd still love to try and slow that stock fan down a little bit. Working harder then it needs to. Slower fan = less noise.