This draws a million point line graph. It takes maybe 3 seconds, requires around 600MB and isn't very useful, but it has no problem handling it.

#! perl -slw
use strict;
use GD::Graph::lines;

our $N ||= 1e6;

my( @x, @y );
push( @x, int rand 1024 ), push( @y, int rand 768 ) for 1 .. $N;
my @sortOrder = sort{ $x[ $a ] <=> $x[ $b ] } 0 .. $#x;
@x = @x[ @sortOrder ];
@y = @y[ @sortOrder ];

my $g = GD::Graph::lines->new( 1024, 768 ) or die $!;
$g->set( no_axes => 1 );
my $gd = $g->plot( [ \@x, \@y ] ) or die $g->error;

open PNG, '>:raw', 'graph.png' or die $!;
print PNG $gd->png;
close PNG;

system 'graph.png';
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