我正在尝试运行8个线程，使IdTCPClient重复扫描一个IP范围。当这些线程运行时，主窗体挂起，滞后。“IdTCClient.connect”是问题所在。有办法解决吗？

unit Unit3;
interface
uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
type
  TTcpThread = class(TThread)
    Idx: word;
     procedure Execute; override;
  end;
  TForm3 = class(TForm)
    procedure FormShow(Sender: TObject);
  private
  public
  end;
var
  Form3: TForm3;
implementation
uses IdTCPClient;
{$R *.dfm}
procedure TTcpThread.Execute;
begin
  for var i := Idx*8 to (Idx*8) + (8-1) do  // 8 IP per Thread
  begin
    var TCP := TidTCPClient.Create(nil);
    TCP.Host :=  '192.168.1.' + i.ToString;;
    TCP.Port := 9999;
    TCP.ConnectTimeout := 500;
    TCP.ReadTimeout := 1000;
    try
      TCP.Connect;
      TCP.Disconnect;
    except end;
    TCP.Free;
  end;
end;
procedure TForm3.FormShow(Sender: TObject);
begin
  for var i := 0 to 32-1 do  // 32 Threads
  begin
    var Thread := TTcpThread.Create(True);
    Thread.Idx := i;
    Thread.FreeOnTerminate := True;
    Thread.Start;
  end;
end;
end.

线程运行时主窗体将冻结/滞后