He wouldn't be as dominant as he was in the late 60s early 70s era. He likely would have a titanic clash with Holyfield. He definitely wouldn't get past Lewis and not Bowe imo. He would struggle with a Bruno or a Mercer or a Bert Cooper. I don't see him beating an early 90s Mike Tyson. An early 90s Foreman might be able to do him in.
Facing so many bigger opponents would probably cause stress to the 205 pound Frazier, but give him some juice and he will become champ