This will slow...
  235ms
  227ms
  236ms
  245ms
  221ms
  222ms
  258ms
  229ms
  228ms
  228ms

This will be fast... (apart from the first!)
  232ms
  181ms
  179ms
  180ms
  178ms
  179ms
  182ms
  179ms
  180ms
  182ms


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

program Project1;

{$mode objfpc}{$H+}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, sysutils, dateutils;

procedure TestPerformance;
var
  i: Int32;
  t: TDateTime;
begin
  t := Time();
  for i := 0 to 100000000 do
    sqr(i);
  Writeln('  ', MilliSecondsBetween(Time(), t), 'ms');
end;

begin
  Writeln('This will slow...');

  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);
  TestPerformance;
  Sleep(100);

  Writeln('This will be fast... (apart from the first!)');

  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;
  TestPerformance;

  readln;
end.