I have a Raspberry Pi 4B and over VNC, glxgears will only give me 1 FPS. But over regular HDMI cable to a screen, then glxgears works like a charm.

So is there any problem with the VNC server inside Raspberry Pi 4B or is it RealVNC that causing this issue?

The internet connection is fast and the Raspberry Pi have the latest Raspberry Pi 64-bit version of Bullseye.

  • What are you expecting to see? You are streaming video across your network.
    – CoderMike
    Jun 30, 2023 at 9:33
  • @CoderMike I'm expecting to see a faster spinning gears. I plugged in the HDMI cable to a monitor and now the graphics works fine over VNC. Can it be that HDMI must be enabled so the GPU works faster?
    – euraad
    Jun 30, 2023 at 9:48

1 Answer 1


RealVNC mirrors the current screen.

On the Pi4 there is no default screen.

If there is no display there is nothing to mirror and normally you see nothing.

There are ways of creating a default or virtual screen without a physical monitor. (My Pi rarely have monitors - due to a shortage of desk space.)

I use raspi-config Display Options/VNC Resolution to set the default resolution.
I have never created a virtual screen with RealVNC (I have used with other VNC servers) but it is possible. You would need to consult the RealVNC documentation.

  • So, how can I create a virtual screen in Raspberry Pi so it will work with glxgears over VNC?
    – euraad
    Jul 1, 2023 at 12:48

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