XNA frame rate spikes in full screen mode

Question

I'm loading a simple texture and rotating it in XNA, and this works.

But when I run it in full screen 1920x1080 mode I see spikes while my texture is rotating.

If I run it windowed with 1920x1080 resolution, I don't get the spikes.

The size of the texture does not seem to matter, I tried 512 texture size and 2048 texture size, same thing happens. Spikes in full screen, no spikes in windowed, resolution does not seem to matter, Debug or Release does not seem to do anything either.

Anyone got ideas of what could be the problem?

Edit:

I think this problem has something to do with the vertical retrace. Set this property: _graphicsDeviceManager.SynchronizeWithVerticalRetrace = false;

you'll lose vsync but it will not stutter.

Answer 1

Use maximised border-less windows to 'simulate' fullscreen mode. I actually prefer games that have this option - it works MUCH better with multiple screens and there's no delay when alt-tabbing out. The main issue is that you can't minimise the game easily so it will cover the desktop unless you use the minimise shortcut or show desktop shortcut.

I use this code in my Game.Initialize() method to do it:

var myScreen = Screen.AllScreens[0]; // Change 0 for other screens

graphics.PreferredBackBufferWidth = myScreen.Bounds.Width;
graphics.PreferredBackBufferHeight = myScreen.Bounds.Height;
graphics.ApplyChanges(); // Not necessary, however this is a method in my code

Form gameForm = (Form)Form.FromHandle(Window.Handle);
gameForm.FormBorderStyle = FormBorderStyle.None;

gameForm.Left = myScreen.WorkingArea.Left;
gameForm.Top = myScreen.WorkingArea.Top;

I'm not sure if there's a performance hit, I haven't checked.

EDIT:

If you want to come out of this mode you need to do this:

Form gameForm = (Form)Form.FromHandle(Window.Handle);
gameForm.FormBorderStyle = FormBorderStyle.Sizable;

gameForm.Icon = System.Drawing.Icon.ExtractAssociatedIcon(
    Process.GetCurrentProcess().ProcessName + ".exe");
// IMPORTANT - XNA loses it's icon when going from no border back to having a border

graphics.PreferredBackBufferWidth = 800;
graphics.PreferredBackBufferHeight = 600;
graphics.ApplyChanges();

Answer 2

A potential explanation found in a Steam forum of all places.

It's a bug in XNA framework's fixed timestep code. I have the same problem.

Only way developers will fix this issue is that they don't use XNA's fixed timestep loop for PC version of the game. They have to make their own fixed step gameloop, but it's really easy to do.

Even official XNA code samples that use XNA's fixed step, stutter on my computer in fullscreen.