SMB/CIFS ISSSUES, directory listings slow/hangs ReadyNAS OS 6.4.2, RN314 4 x 4TB (Seagate)

Hi Guys, I am new to this forum as a poster, but have been on here before looking for help on issues.

I have a RN314 4x4TB thats just over 2 years old. ReadyNAS OS 6.4.2, 4GB RAM (upgraded the ram from 2 - 4GB more than a year ago and absolutely no issues with it)

Works perfectly but for SMB/Cifs issues. 

SMB / Cifs hangs when loading the directory with files in it, and times out, Directory listings of directories where there is no files in seems fine.

Sevices activated and running:

SMB/Cifs = serious issues = 2 Win 10 Clients, 1 OS X, 2 x "FileBrowser" app on iOS

PlexMedia Server = works perfectly, with 1 Roku client, 2 iOS, 1 Mac, 1 PC Win 7, 1 PC Win 10,  connected at variable alternate times.

Itunes Music Server = Works perfectly with 3 different PC's connected to it at alternate times.

AFP = Time Machine Backup Server (Dedicated private) = Works perfectly 3 x OS X clients with seperate usernames and seperate quota's 

SSH active and also slow (had to activate it and check what is going on after my warranty ran out) To try and see what is wrong here.

ReadyCLOUD & ReadyNAS Remote, works = SAME issue, can connect to the NAS from outside, but when doing directory listings times out as well.

Https & HTTP access on LAN and WAN Access through ReadyCLOUD, and ADMIN Through the Netgear VPN service WORKS.

4 Users = 1 admin (me), (2 Time machine only), (1 Time machine, and view of 1 share folder only). 

 My HOME LAN

Virgin Super Hub Fibre,

All CAT 6 Gigabit Ethernet connection, Netgear Gigabit 8 port ehternet switch, except for iOS devices which is wireless. 

4 x MAC OS X, (1 Connected to SMB as admin), (3 x Connected to Time machine of which 2 no SMB access, and 1 VIEW ONLY, one folder only)

2 x Win 10, (2 Connected to SMB as admin)

1 x Debian Server connected to (1 SMB share as admin)

2 x iOS devices connected to (SMB with app "filebrowser" as admin)

I hope I don't have too much info here, but basically I noticed SMB issues for a very long time with my iMAC, and very occasionally with my windows 10 machine, the filebrowser app on iOS were lightning fast and never had any issues with connecting or file browsing. I believed the issue with my iMAC was OS X related and it annoyed me so much, I could not get any work done ever, which made me make my iMac run Windows 10 in dual boot Bootcamp just because I could not be asked waiting for server to connect and directory listings whirling away even in the same finder window when clicking back or to open a folder, utterly utterly painful. 
Recently, Windows 10 was doing the exact same thing, windows explorer would time out, and crash explorer, with certain folders taking ages to load and then times out. 

The filebrowser app on iOS was doing the same thing, Directory listings with folders only would work, but the minute you open a folder with files in it, it whirls for ages and times out as well. 
All this made me believe its a ReadyNAS issue, as I don't have the same issues with my (Debian server Dell Poweredge) that I have on the network. 

I enebled SSH access to the NAS, and checked my files and file permissions, I am the owner of all files and group owner is admin, I am in the admin group, all as expected. and all permissions on all files and folders are (rwxrwxr-x)

I need help with this, I hope there is someone else that can help out, or that has the same problem, afterall this is what this box is supposed to be, a Network Attached Storage, and at the moment I struggle with accessing files over the LAN.

Thanks, 

Dion