By default the Appliance uses 2 CPU. However I've had performance issues recently as I add more and more backups. I can assign more vcpu's to the VM - will Acronis use them if I assign them? Or should I start looking into splitting up my installations?
Typically CPU is not the primary resource during backup - it's more dependent on RAM rather than CPU. CPU is used for compression and encryption activities only and is rarely a bottleneck even though up to 4 CPUs can be used by the appliance. Also in Acronis Backup for VMware it doesn't make sense to add more than 4GB of RAM since it won't use RAM exceeding this value during the backup operations.
The general recommendation is to backup up to 50 VMs using single appliance of Acronis Backup for VMware (in case of Windows Agent installation type this number may be greater of course).
I'm backing up 1 at a time. I'm sure to space them out equally during the night. Yet I still get 100% processor usage warnings while backing up in Vmware. These are rather new Xeon processors too. I have about 30 servers I backup throughout the day.
By default the actual app installed 2 GB of ram so I'll increase to 4 to see if there is any improvement.
You think this is normal for 1 backup to run?
This CPU usage doesn't look normal. Besides increasing the RAM it makes sense to try deploying a fresh new appliance and perform a test backup using it to check CPU consumption - the issue might be related to the original appliance internal disk contents (excessive logs amount or something else).