C++ Windows link subsystem question

When using the windows SDK to compile a program writen in C++, if I specify -subsystem:windows,6.1, the width of the window is smaller. If I don't, or do -subsystem:windows without the 6.1, the width is normal.

I'm curious why this does this, and if there's a way to make it stay the same width regardless of what command line I pass to link.

EDIT: So it's also height, height and width are both different. And if i look at it with Inspect.exe, it says the size is the same each time.

EDIT2: Also it's a window application created with CreateWindow, not a console.

EDIT3: Here's the full code that initializes my window:

wcex.cbSize         = sizeof(WND开发者_JS百科CLASSEX);
wcex.style          = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc    = WndProc;
wcex.cbClsExtra     = 0;
wcex.cbWndExtra     = 0;
wcex.hInstance      = hInstance;
wcex.hIcon          = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(SMALL_ICON));
wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground  = (HBRUSH)GetStockObject(BLACK_BRUSH);
wcex.lpszMenuName   = NULL;
wcex.lpszClassName  = g_szWindowClass;
wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(SMALL_ICON));

g_hMainWnd = CreateWindow(
    g_szWindowClass,
    t_szWindowTitle,
    WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX,
    CW_USEDEFAULT, CW_USEDEFAULT,
    392, 250,
    NULL,
    NULL,
    hInstance,
    NULL
);

And I resize the window with this:

SetWindowPos(hWnd, NULL,
    (GetSystemMetrics(SM_CXFULLSCREEN)/2)- (392/2),
    (GetSystemMetrics(SM_CYFULLSCREEN)/2) - (250/2),
    392, 120, SWP_NOZORDER);

I'm suspecting you are specifying some windows styles that are only supported in Windows7 (Win7 = 6.1). Post the full CreateWindow call with arguments and also try turning off Aero. The window border may be included in the width/height for example in one scenario.