unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    Timer1: TTimer;
    Label1: TLabel;
    procedure Timer1Timer(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  d : LongWord;
  d1 : LongWord;
  d2 : LongWord;
  n : Byte;
implementation

{$R *.dfm}

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  asm
    rdtsc
    mov d1, eax;
  end;
  Label1.Caption := IntToStr(d1 - d);
  d := d1;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  asm
    rdtsc
    mov d, eax;
  end;
end;

end.

const
ID_BIT=$200000; // EFLAGS ID bit

function GetCPUSpeed: Double;
const
  DelayTime = 500;
var
  TimerHi, TimerLo: DWORD;
  PriorityClass, Priority: Integer;
begin
try
  PriorityClass := GetPriorityClass(GetCurrentProcess);
  Priority := GetThreadPriority(GetCurrentThread);

  SetPriorityClass(GetCurrentProcess, REALTIME_PRIORITY_CLASS);
SetThreadPriorit(GetCurrentThread,THREAD_PRIORITY_TIME_CRITICAL);

  Sleep(10);
  asm
    dw 310Fh // rdtsc
    mov TimerLo, eax
    mov TimerHi, edx
  end;
  Sleep(DelayTime);
  asm
    dw 310Fh // rdtsc
    sub eax, TimerLo
    sbb edx, TimerHi
    mov TimerLo, eax
    mov TimerHi, edx
  end;

  SetThreadPriority(GetCurrentThread, Priority);
  SetPriorityClass(GetCurrentProcess, PriorityClass);

  Result := TimerLo / (1000.0 * DelayTime);
  except end;
end;


procedure TForm1.Button1Click(Sender: TObject);
var cpuspeed:string;
begin
cpuspeed:=Format('%f MHz', [GetCPUSpeed]);
edit1.text := cpuspeed;
end;