I've got a Synology DS412+ that I've been relatively happy with after owning it for a few months, but lately I've been pretty disappointed with the read/write performance (15-20MB/sec). I originally created a Synology Hybrid RAID volume with 1 2TB Western Digital Green drive and 2 2TB Seagate Barracuda Green drives, and performance was good but getting weaker as I filled it up (at one point I had 300GB free out of 3.4TB). I then added a 3TB Seagate 7200RPM drive to get some more free space (that took 24 hrs, oy) and now have about 35% free but my read/write speeds are still pretty terrible. Is there something I'm doing wrong? Should I have gone with a simple RAID 10 instead (requiring me to get another 3TB Seagate)? Or is it because I'm using Green drives?