(Sanity Check) Another ZFS performance thread

I searched around but couldn’t find anything quite similar. With so many configurations it’s hard to get a read on what I should expect, so here goes. To note, the pool in question is the NetApp - so the performance is more than enough for what I need, it is concerning.

System:
FreeNAS 11.3u1
E3 1220v3
32gb ECC RAM (Can’t remember the speed)
Mellanox Connect X-2

STORAGE
(ashift is 12 across all but boot)
4x 3TB WD SATA (Raid10)
5x 4TB Seagate (RaidZ, single vdev)
3x 500GB Samsung SSDs (stripe)
DS4246:
9x HGST SAS (3x RaidZ)

Use case:
WDs: backups from other vdevs and machines at home
Seagates: Virtual machines / SMB shares
SSDs: Virtual machines
NetApp: Movies

Testing:
New dataset with compression, atime, and Sync disabled.
Based on a quick guide, I used DD to test making sure it would go beyond my RAM…
dd if=/dev/zero of=tmp.dat bs=2048k count=50k
this got me ~250mbyte/s
dd if=tmp.dat of=/dev/null bs=2048k count=50k
this got me ~450mbyte/s

With 9 disks in RaidZ across 3 vdevs, I was hoping for around 800-ish either way. What’s interesting is I started a scrub, and zpool iostat showed around 1gbyte/s…

I created a SMB share, and it performed equally to the DD testing (over 10gb/s card).

Any thoughts?

**Bonus - my 5 disk vdev is about 60% full and hits 400/400 read/write, but it has a SLOG device.

Are the 3 types of storage all on the same zpool? Also, how can the SSDs be raid 0 and 3x raidZ?

Each line I wrote out is a pool. I misspoke - 3 vdevs with a single disk, striped (removed RaidZ from post).