Stage3D Performance In Windows

For my app I run Stage3D, When I add more view I get low fps. I use TechPowerUp GPU-Z  the GPU usage 100%  but cpu usage 10%;

So I test code:

stage.addEventListener(Event.ENTER_FRAME, loop);

stage.framerate = 30;

function loop(e:Event):void

{

     Context3D.clear();

     Context3D.present();

}

The GPU usage 30%-45%;

Same way I use c++ code follow this:

while(true)

{

     PeekMessage(&msg, NULL, 0, 0, PM_REMOVE);

     HRESULT hr = device->TestCooperativeLevel();

     if(FAILED(hr))return FALSE;

     device->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );

     hr = device->Present( NULL, NULL, NULL, NULL );

     Sleep(10);//About FPS is 100

}

The GPU usage 10%

Then I use PIX for windows and capture A single frame like this:

I only wrote two code But stage3D call 190 Direct3D api.

I do not know if this is a key factor affecting performance. But in fact Stage3D is very easy to reach the performance bottleneck.

I do not know what method can be faster and more efficient? Who can help me.