Yes, i know FreeNAS uses all the drive space for itself, i was just unsure about it speed and reliability. From what you've said i'd go straight with an USB, but from what djdwosk97 said i simply can't if i wanna use Skylake. And yeah, i've put freenas on a VM and used for a while, that's what made me chose it, i like it a lot and it's great and simple for what i'm doing. Thanks a lot for answering.
Thank you really much for the time you spent to answer this. And you configuration is really great, it's 200€ less than what i did, but it's still badass. I might go with Haswell then, i wo