Оптимизация приложения "менеджер закачек"

var
  str :tmemorystream;
  IdHTTP: TIdHTTP;
  i: Integer;
  fname : string;
begin
  pb1.Position := 0;
  pb1.Max := lst1.Items.Count;
  for i := 0 to lst1.Items.Count-1 do
    begin
      fname := copy(lst1.Items[i],pos('img_',lst1.Items[i])+1,length(lst1.Items[i])-pos('img_',lst1.Items[i]));
      str:=TMemoryStream.Create;
      IdHTTP := TIdHTTP.Create(nil);
      IdHTTP.Get(lst1.Items[i],str);
      str.SaveToFile(Directory + '\i' + fname);
      str.Clear;
      IdHTTP.Free;
      pb1.Position := pb1.Position + 1;
    end;
  ShowMessage('Скачивание успешно завершено!');

if not FStopAll then
      RunThread(FThreadCount)

if not FStopAll then
      RunThread(FThreadIndex)

procedure TfThreadsMain.RunThread(index:Integer);
var
  th : TGetThread;
  link, fname : string;//////////////////////////////////
  i : integer;////////////////////////////////////////////
begin
  link := m1.Lines[index];/////////////////////////////
  i := LastDelimiter('/', link);///////////////////////////
  fname := Copy(link, i + 1, Length(link) - (i));//////
 
  th := TGetThread.Create(m1.Lines[index], extractfilepath(ParamStr(0))+'Download\'+fname,ThreadTerminated);////
  th.Resume;
  Inc(FThreadCount);
  Inc(FThreadIndex);
end;

k:=0;
while k < memo.Lines.Count-1
  for i := 0 to ThreadMaxCount-1 do
    begin
      if i<m1.Lines.Count then
        RunThread(i);
    end;
k:=k+i;