Browser (desktop) makes Fan run too much + internet at least half-speed (Mac, since Catalina update)

[WildFruit]

Thanks. It is very consistent in always being around half-speed (or slower) of what it should be and what Safari shows. It looks to be the exact same issue as reported by 2 other users from a year ago ( Slow Internet Speeds compared to Safari - Fiber Gig Internet - #14 by afdy ).