function GetCpuSpeed: Comp;
{ function to return the CPU clock speed only.}  
{ Usage: MessageDlg(Format('%.1f MHz', [GetCpuSpeed]),
mtConfirmation, [mbOk], 0); }  
var  
   t: DWORD;
   mhi, mlo, nhi, nlo: DWORD;  
   t0, t1, chi, clo, shr32: Comp;  
begin  
   shr32 := 65536;  
   shr32 := shr32 * 65536;  
  
   t := GetTickCount;  
   while t = GetTickCount do begin end;  
   asm  
     DB 0FH  
     DB 031H  
     mov mhi,edx  
     mov mlo,eax  
   end;  
  
   while GetTickCount < (t + 1000) do begin end;
asm
DB 0FH
DB 031H
mov nhi,edx
mov nlo,eax
end;

chi := mhi;
if mhi < 0 then chi := chi + shr32;

clo := mlo;
if mlo < 0 then clo := clo + shr32;

t0 := chi * shr32 + clo;

chi := nhi;
if nhi < 0 then chi := chi + shr32;

clo := nlo;
if nlo < 0 then clo := clo + shr32;

t1 := chi * shr32 + clo;

Result := (t1 - t0) / 1E6;
end;