Seasonic x550, is this normal or RMA?

[baobeiiii]

I just got my first seasonic x psu. I have one question though. At first I just tested it by shorting the green wire to the black one and connecting a fan. No coil wine, just a slight buzz that couldn't be heard from a few inches away.

After connecting it to mobo and powering up the system, it has a quiet coil wine and 'beeping' sounds that repeat about every 2 or 3 seconds. Is that normal? I can't really hear it from more than 3 feet away and this is outside of the case on a table (i also have exceptionally good hearing).

Bear in mind this is just on an idle system that is on the bios only, i haven't stress tested it yet. I'm hoping i get re-assured it is normal, already had to return a case today that had really bad damage and quality issues.