Netgear 7000P USB3 slow transfer speed with external enclosure only?

[Shecky]

Recently purchased a netgear 7000P. ALl is well EXCEPT the one HD I want to use as a USB attached strorage is performing slow vs other drives.

Here is the tests I have run:

First to test transfer drive speed directly connected to the computers USB3 port, 3 drives tested
Copying a 10 gb movie file from drive to desktop

WD passport 1 TB: approx transfer speed: 85 MB/s
Seagate 1 TB extension portable drive: 125 MB/s
WD 3.5" 2 TB blue HD in an enclosure. USB3 connection (has its own power supply): 130 MB/s

The WD in the enclousure is the drive I want to use as the router USB connected drive

Problem is, when I connected it to the router, the transfer speeds for that drive in particular drop.
Connected to router USB 3.0 port, copying through network to gen8 wired computer, same 10 gb movie file:
WD passport 1 TB: approx transfer speed: 78 MB/s
Seagate 1 TB extension portable drive: 78 MB/s
WD 3.5" 2 TB blue HD in an enclosure. USB3 connection (has its own power supply): 30 MB/s ????

Any ideas?