G-RAID 8TB Thunderbolt 2 speed v USB 3.0

I just got the G-RAID 8TB with Thunderbolt 2 last month (Aug 2016) and to my disappointment my RAID 0 configuraton will only go as fast as 321MB/s for WRITE and 326MB/s for READ!
Not even close to the website note for “Up to 480MB/s”.
I also tryied my USB 3.0 conection and thought it was going to be slower but its the same speed as my Thunderbolt 2 connection…so why pay more for Thunderbolt 2 :frowning:
I have the G-RAID with Thunderbolt 2 unit running off my the latest iMac 5K (4GHZ Intel Core i7) so its not the iMac end holding up the drive.
The response back from the support team was that the declaimer on the site for my Thunderbolt model “Up to 480MB/s” is only true for the 12TB or more versions…not happy :frowning: