Hey ok. Maybe I jumped the gun. So I just powered on my PC and wouldn't you know it, the SX600's fan wasn't spinning! It even stayed quiet during idle, that is until I had to transfer some files from one SSD to another. The fan started making a false start kind of motion about a dozen times, then finally kicked in.
Once the transfer was done I let it sit doing nothing for 15 minutes, the fan never turned off. Just that chugging sound from the fan.
Tried putting it to sleep (after only file copying) and waking it up. The fan didn't start up immediately but it did false start a couple of times and then spin up. Obviously there's no more than idle load after waking up. It must be the PSU temp sensor that's still warm.
Man I wish I had a temp meter to figure out if it really needs to be on at such a load load.
Also, I got a response from SilverStone support. They claim there's no difference between the v1.0 and v1.1. Now they might mean there's no difference in the fan, but they answered that there was no difference between either PSU. They also said that if the fan wasn't off when I booted that its defective.
It looks like mine isn't defective after all, its just that the fan kicks in once you start doing anything.
I'm tempted to flip the PSU around and have my rad fan blow into the PSU's intake fan. Maybe it'll help keep the fan from starting so early.