So I did a non-scientific test on my Raspberry Pi at home with a 4G card that has typically been my 'move an .iso around' it is a 'class 10' card from Microcenter Warehouse. Using this perl program:

   #!/usr/bin/perl

   use strict;
   use warnings;

   my $letters = "ABCEDEGHIJKLMNOPQRSTUVWXYZ-";
   my $range = length $letters;

   while (1) {
       foreach (1..16) {
           my $nm = "A";
           foreach (1 .. 15) {
               $nm .= substr($letters, rand($range), 1);
           }
           open(my $fh, ">", "$nm.delete-me");
           foreach (1 .. 128) {
               $nm .= substr($letters, rand($range), 1);
           }
           print $fh "$nm\n";
           close $fh;
       }
       `sync`;
       `rm *delete-me`;
   }

Killed it dead in 3 hrs 18 minutes. Your mileage may vary.

May not be 'first hand' enough though.