Jahed Ahmed

Booting to DisplayPort

I've had my computer for over 5 years now and one thing has always bugged me: whenever I switch it on, the initial boot screens default to my secondary DVI monitor instead of my primary DisplayPort monitor. It was a minor nuisance so I looked passed it. That is, until my secondary monitor started giving off a high-pitched whine; something to do with cheap capacitors but that's for a different post. After unplugging it, my boot screens were still using DVI even though nothing was plugged in! Why?

Both monitors are connected through my Nvidia graphics card so I assumed it's something to do with UEFI because every boot up problem is almost always to do with that. I looked around, fiddled about and found a fix. I have an ASUS motherboard, so your options may be different but it should be more or less the same.

  1. Boot to BIOS Settings (press F2 at BIOS boot screen).
  2. Switch to Advanced Settings.
  3. Choose "Boot" settings along the top.
  4. Find "Compatibility Support Module (CSM)". This should currently be "Enabled". You have two options to fix the problem:
    • Option 1: Under CSM there are multiple settings. Change PCI Boot priority from Legacy to EFI.
    • Option 2: Disable CSM entirely. This may cause issues during boot. If it does, enable it again and try Option 1.

And that's it. Problem solved. At least for me.

Thanks for reading.

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