I don't run an antivirus though. I'm pretty sure there's an issue with cpu thread selections on some CPUs and that's what I'm encountering atm.
Run it using a different command, like
vanitysearch -o output.txt 1a.
If it consumes all of your CPU resource, then it's not "
that issue".
I think the problem is the way you want to use vanitysearch, it's not meant for creating bulk random addresses IMO.
I'm pretty sure that there are other tools that can do that bulk address generation better (
I don't have one however).