Как узнать объём видеопамяти?

IDirectDraw7* pDirectDraw;
DWORD m_uLocalVidMemorySize, m_uTotalVidMemorySize, m_uAGPVidMemorySize;

HRESULT hr = CoCreateInstance(CLSID_DirectDraw7, NULL, CLSCTX_ALL,
                              IID_IDirectDraw7, (void**) &pDirectDraw);
if(!FAILED(hr))
{
  hr = IDirectDraw7_Initialize(pDirectDraw, NULL);
  if (!FAILED(hr))
  {
    DDSCAPS2 QueryCaps = { 0 };
    DWORD dwTotal, dwFree;
    QueryCaps.dwCaps = DDSCAPS_LOCALVIDMEM;
    hr = pDirectDraw->GetAvailableVidMem(&QueryCaps, &dwTotal, &dwFree);
    if (!FAILED(hr))
      m_uLocalVidMemorySize = dwTotal;
    QueryCaps.dwCaps = DDSCAPS_TEXTURE;
    hr = pDirectDraw->GetAvailableVidMem(&QueryCaps, &dwTotal, &dwFree);
    if (!FAILED(hr))
      m_uTotalVidMemorySize = dwTotal;
    m_uAGPVidMemorySize = m_uTotalVidMemorySize - m_uLocalVidMemorySize;
   }

  pDirectDraw->Release();
}
   Label24->Caption=m_uLocalVidMemorySize;