Code:

// Works only on Windows NT systems (WinNT, Win2000, WinXP)

uses psAPI;

procedure TForm1.Button1Click(Sender: TObject);

var

pmc: PPROCESS_MEMORY_COUNTERS;

cb: Integer;

begin

cb := SizeOf(_PROCESS_MEMORY_COUNTERS);

GetMem(pmc, cb);

pmc^.cb := cb;

if GetProcessMemoryInfo(GetCurrentProcess(), pmc, cb) then

   Label1.Caption := IntToStr(pmc^.WorkingSetSize) + ' Bytes'

else

   Label1.Caption := 'Unable to retrieve memory usage structure';

FreeMem(pmc);

end;