The performance is fine. It's been years since I ran my steam library on HDD, so I don't have anything really to compare to (except my own expectations and impatience). The NAS is running 7 SSD drives in zfs raid, and exports a 1TB volume over iSCSI, via a dedicated 10GBe fiber link. Anecdotally, I will often boot into games faster than friends who have a local SSD (so I think this means that I've gotten disk perf to be "good enough" that other hardware components start to dominate things like load times)