next unless /$V/;

##</code><code>##

C:\test>1036737 -V=500 < numbers.tsv
Took 19.138550 seconds ## without pre-filter
Kept 2005 records

C:\test>1036737 -V=500 < numbers.tsv
Took 1.755853 seconds ## with pre-filter
Kept 2005 records

##</code><code>##

C:\test>1036737 -V=5 < numbers.tsv
Took 18.765492 seconds ## Without pre-filter
Kept 1944 records

C:\test>1036737 -V=5 < numbers.tsv
Took 20.232294 seconds ## With pre-filter
Kept 1944 records