I do some exploration of the problem and result is, that if i am using Direct3D renderer, value of Now() DOES NOT CHANGE, if used any else renderer, it is OK and value DOES CHANGE. Try this with plasma demo - i added one marked line:
[pascal]
procedure TMainForm.TimerRender(Sender: TObject);
var
i, j: Integer;
begin
with PowerDraw.Device do
begin
Clear($FFFF0000);
BeginScene();

for j:= 0 to (PowerDraw.Height div 256) do
for i:= 0 to (PowerDraw.Width div 256) do
RenderEffect(Images[0], (i * 256), (j * 256), 0, effectNone);

Fonts[0].TextOut('FPS: ' + IntToStr(Timer.FrameRate), 4, 4, $FFFFFFFF, effectNone);
{added line} Fonts[0].TextOut('Time: ' + FormatDateTime('HH:MMS.ZZZ', Now()), 4, 40, $FFFFFFFF, effectNone);

EndScene();
Present();
end;
end;
[/pascal]

second mystery is, that on my computer in Direct3D mode minutes are 3 minutes sooner than right time (and of course doesnt change) :?: