NFS very slow from Ubuntu 16.04 Server

I have an PC with Ubuntu 16.04 serving as server for my files.
I configured a drive as NFS share.
I did these settings in /etc/exports
Export media to all IP address under 192.168.1.X

The share is visible in OSMC on a Pi 3 and i can choose it as video source.
It appears to be very slow. a file takes up to 20 seconds and plays for a few seconds before it stutters.

The same file configured as SMB share works just fine.

NFS should be faster. Any suggetions how to configure it right?
I seem to make a mistake somewhere.
Do i have to mount the share with kernel mode nfs?
Any other suggetions?

Not necessary, but recommended. Try /etc/fstab approach.

Just tried that.
My /etc/exports settings for the server is

My settings fot /etc/fstab on OSMC is
168.2.105:/home/user/acd. /home/amazon nfs ro,x-systemd.automount,noauto 0 0

OSMC on the Pi 3 gets very slow and the video stutters.
Again with SMB the files play fine.

To add my advancedsettings.xml:


I use NFS with no trouble (and rw too) using the following options:

I tried using rsize=8192,wsize=8192 also but had problems getting this to work for all hosts - specifically QNAP NAS devices.