Good news!
I’ve spend the day rebuilding the server. I’ve completely overhauled the system, replacing what was an aging AMD octacore with a new Intel server.

New specs are:
CPU: Intel E3-1245v5 3.5GHz 4 Core, 8 threads.
Motherboard: INTEL S1200SPL
RAM: 32GB (4x8GB) Crucial 2400Mhz ECC
Other components: Nvidia NVS300 gfx card, quad DVB-T tuner, additional SATA raid card for the 11 hard disks in the two raid arrays.
All houses in a Cooler Master Cosmos II Full Tower.

All in all, the migration has been very smooth. I’ve been able to get all the VMs up and running again without much fuss. I didn’t realise that remote console through the Intel BMC web console was not possible without an additional component, so I’ll be ordering an Intel remote management component (AXXRMM4LITE2) very soon.