Slow / Active Tasks Failing / Task Server Slow

Hello,

Using Mac mini latest i5 8gb ram 1gb eth

Yosemite 10.10.2 Server 4.0.3 ARD 3.8.2

Clean install.

Clients: MBPro's Yosemite 10.10.2 all updates. ARD client 3.8.2 (not bound to OD yet)

Managing 180 devices about to connect more.

Issue:

When deploying Packages 5 packages (5gb) for installment on groups (student mac books in class lots 20 - 30) the Active task / server task fails with error fail on all.

If I deploy to single MBPro packages copy / download to machine in about 1min then install successfully. total process 6min.

then run another package install for updates another 5 min Successful.

If I try to send to 2 or more MBPro's it takes up to 1hour for 1st package and can see message failed on all.

Also seeing failures on "not authorized" "communication error"

For troubleshooting steps.

1. server and MB on same 48port switch cabled

2. MB all powered and PS modes disabled.

3. Confirmed WIFI is off.

4. Copied package files to the server rather than the NAS

5. Rebooted all gear switches routers server (actually did that first)

6. isolation network

All connected and running with local admin user and privileges.

short of uninstalling ARD and trying again.

Any other useful pointers help would be greatly appreciated.