Yes, I am trying it since some hours to find out max. OC settings for each GPU to run stable (cause I have cards from different models/manufacturers on that rig, but is also interesting for same model/manufacturer as I found out now).
I have only a Celeron G3900 2.80 GHz and 4 GB RAM on that rig and it seems to be good.
I am not sure if it does really need more CPU/RAM. Yes there are more processes in that case, but maybe smaller processes instead of one big process.
An interesting thing would also be to name each card as an own worker. For example Rig1.GPU1, Rig1.GPU2, Rig1.GPU3, etc.
But I am still unsure, if that does have any other impacts.