Slow access to USB3 attached NFS share

Hi,

I do not have a lot experience with NFS shares and I am experiencing a really slow NFS access. Here below are my setup.

I have a decent laptop running openSUSE 13.1 and I connect a USB3 hard drive (formatted as NTFS) to the USB3 port of the laptop. I configured NFS shares as below.

/home/user/ 192.168.1.0/24(ro,async,insecure,no_subtree_check,no_all_squash,anonuid=1000,anongid=100)
/media/USB3/ 192.168.1.0/24(ro,async,insecure,no_subtree_check,no_all_squash,anonuid=1000,anongid=100)

When I try to access the USB3 share from a android based TV set top box wirelessly, the file listing, video playback (I do have some blue ray rips though) are really slow and sometime not even responsive...

I tuned NFS by increasing the read and write memory allocation but it does not seem help. Is there any special USB3 driver I should install on openSUSE? The laptop is wired into my network and set top box is connected via 802.11n WIFI (showing 72mbps for speed)

Any other tweak I should apply?

Suggestions are appreciated.

/S