Pleasantly surprised. popped a Toshiba N300 14TB into my DS418J (yes, i know it's not on the supported list, i just like living at the edge lol). Just to see if i would get any surprises, created a single volume on a SHR 1 drive pool. While verifying, i simultaneously am writing 7TB to it (encrypted share), and running an extended SMART. Normally, i see other drives take about 20-24 hours just to verify - this one just finished verifying after 4.5 hours. Writing and SMART are still in progress though. Given the load, am getting about 65-80MBps transfer speed.
Despite the work, it is running at 39'C vs the other 3 idle HGST 6TB at 45'C. Will push it for a few more days, before adding to array. Crossed fingers.....