Hi albert,
Well the 4 TB limit as the maximum capacity has long been passed since the ready availability of 3TB and 4TB drives, which in JBOD and RAID 0, or 2 Standard drives for that matter provide 6 and 8TB max. capacity. I have personally used both in the 320 and have had approx. 6.7TB (in the 2x4TB configuration and 5TB in the 2x3TB) of data on those in both JBOD and RAID 0 without any discernable issues, that is, I can add, delete, stream etc, without anything causing issues. My best guess is that Dlink did not fill two 2TB drives on the original units to test drive compatibility either, so given all the factors, I am pretty confident that these larger drives will work in a similar fashion. My findings are preliminary for sure, but they are all positive. The issue you raised is of course valid and neither your point or my findings are a recommendation to purchase either these WD 6TB drives or the similiar findings for the Seagate 6TB drives reported earlier. Since there has been no other reported success or failure on the 320, the next guy who wants to spend the kind of $ necessary and then take the time to check each format with up to 10TB of data on each....please report asap, thanks.