This sounds logic, but this next test, still shows more or less 20% difference.

for($i=0;$i<100000;$i++){
    if("test$i" =~ /(dest|\d)/){
        # do stuff;
    }
}

for($i=0;$i<100000;$i++){
    if("test$i" =~ /dest/ || "test$i" =~ /\d/){
        # do stuff;
    }
}
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