See perlre. The first question is answered by "character classes". For example, [/()] will match a forward slash, an opening parenthesis or a closing parenthesis.

my @words = split m![/()]!, $line;
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The second question can be answered for example by using positive lookahead. For example, (?=Ghz) will make sure that there is the word Ghz following the current position.

if ($line =~ m!(.*)(?=Ghz)!) {
    print "Found $1 with a 'Ghz' specification\n";
};
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Thinking about it, you don't even need the positive lookahead.