Will User Profile "Start Full Synchronization" affect access/performance?

I have a user whose AD profile was corrected from domain\jon.smth to domain\jon.smith. For some reason the user profile Account Name is still showing up with the domain\jon.smth name.

Confirmed that last incremental sync ran last night, with 0 uncompiled.

Got a suggestion to run a Full. Sound right? Will users be able to access their Audience Targeted content during the Sync?

Thanks!