I have discovered that too much information is being processed to simply display a percentage completed with the Invoke-DatabaseBuild command. I suspect other SQL Change Automation powershell commands are also utilizating the same behavior.

By turning the powershell progressbar off via the ps setting.

$ProgressPreference = "SilentlyContinue"

I improved a single database build performance:
From: 4 minutes -> To: 37 seconds.

I suspect there's alot of data serialization and deserialization taking place within SQL Change Automation update progressbar code to do a simple progressbar reporting update.

This code within sql change automation needs to be looked at more closely to improve the performance.

At minimum a flag on all SCA powershell commands that utilize the progressbar should be made available to disable it.