I'm using an AOC Q27G40XMN with a Ryzen 7 7800X3D, Sapphire Nitro+ Radeon 9070 XT, Aorus Master X870E X3D motherboard, and a 1000W Shift power supply. Over HDMI, the splash screen and BIOS display normally. With DisplayPort, the splash screen is extremely pixelated, and entering BIOS causes the monitor to go blank while its power indicator remains on. The same thing happens when trying to enter BIOS through Windows. I'm using the DisplayPort cable included with the monitor. HDMI works reliably from both the graphics card and motherboard, but I'd prefer to use DisplayPort for the monitor's higher refresh rate. Is there a setting, firmware update, or compatibility fix that would let BIOS display correctly over DisplayPort?
2 Answers
A more expensive HDMI cable probably won’t fix the BIOS issue. HDMI’s lower refresh-rate limit may matter for reaching 180 Hz, but the missing BIOS image is more likely a DisplayPort UEFI compatibility or link-training problem. Try another certified DisplayPort cable, a different DisplayPort input on the monitor, and temporarily disable high-refresh or adaptive-sync features in the monitor’s on-screen menu. Keeping an HDMI cable connected as a backup is also sensible in case you need reliable BIOS access.
DisplayPort can be unreliable during UEFI startup because of how the monitor and GPU handle low-power states before the operating system loads. Check the motherboard’s firmware settings for a UEFI or pre-boot display resolution option, and try different resolution or compatibility settings if available. It may also be worth testing the monitor from the motherboard’s video output, although that depends on the integrated graphics being enabled. Make sure the motherboard BIOS and related AGESA firmware are current.
The motherboard is already on the latest BIOS, including a newer beta version that didn’t change anything. CSM and Secure Boot didn’t help either. HDMI works every time from both the graphics card and motherboard, so the problem seems specific to this DisplayPort connection.