my @size=(100,1000,10000,100000);
   foreach(@size){
     my $size=$_;
     print "size=$size\n";
     my $now = 8;
     my %url = ( monday => { @{[map(($_,1), (1..$size))]} } );
     timethese(0, {
       Grep => q{ $now = (sort grep {$_ <= $now} keys %{$url{'monday'}
+})[-1]; },
       Ternary => q{ $now = ($now < $_ && $_ < 8 ? $_ : $now) for keys
+ %{$url{'monday'}}; },
       Max => q{ foreach ( keys %{$url{'monday'}} ) { $now = $_ if $_ 
+> $now }; }
     });
   }
[download]

I think I am onto something... I don't think the code posted in teh original question really benchmarks what the user thinks it does... I'm crafing a new reply to the original question that should be up soon.