// returns total of physical memory installed (read-up recognized) 
function GetMemoryTotalPhys: dword;
var
recMemoryStatus: TMemoryStatus;
begin
// sets record size
recMemoryStatus.dwLength := SizeOf(TMemoryStatus);

// retrieves global memory status (WinAPI)
GlobalMemoryStatus(recMemoryStatus);

// sets result with total amount of memory
result := recMemoryStatus.dwTotalPhys;
end;

procedure TForm1.Button1Click(Sender: TObject);
var memoryMB:cardinal;
begin
 memoryMB:=GetMemoryTotalPhys;
 memoryMB:=((memoryMB div 1024)div 1024);
 showmessage('RAM: '+ inttostr(memoryMB)+ ' MB');
end;