Multiple Monitor Setup

Hey everyone, I’ve run into a strange issue with my multi-monitor setup and could use some help figuring out whether this is a monitor or GPU-related problem.

I’m using a system with 4 monitors connected via DisplayPort (DP #1 through DP #4). Here’s what’s happening:

Monitor 1 (primary, connected to DP #1) stopped showing video. It only displays the manufacturer’s logo at startup, then goes black.

I tested Monitor 1 by connecting it to DP #2, #3, and #4 — still no video.

Plugged Monitor 2 into DP #1 — video works fine.

This led me to believe Monitor 1 was faulty, so I ordered a replacement.

However, things got weirder today:

I also have a small 7-inch display connected to DP #4. When both the 7-inch monitor and the replacement monitor are connected, neither shows video.

If I disconnect the 7-inch monitor from DP #4, video comes back on the main display (DP #1).

If I unplug the main monitor and plug the 7-inch into DP #1, video works on the 7-inch.

This behavior seems inconsistent. Could it be a GPU issue, some DisplayPort bandwidth or power limitation, or are the monitors at fault?