How to Fix Stuck at 60Hz / 144Hz Not Available on the BenQ MOBIUZ EX2780Q

Causes

• Connected on an input or cable that cannot carry 144Hz — the EX2780Q reaches its full 2560x1440 @ 144Hz over its DisplayPort 1.4 input. An older HDMI 1.4 cable, a low-speed DisplayPort cable, or connecting through the single USB-C port (which BenQ notes does not even deliver power and is not intended for full-bandwidth 144Hz output) can lock the panel to 60Hz.
• Refresh rate left at 60Hz in the OS — the monitor ships at a default and Windows/macOS will often pick 60Hz until you explicitly raise it in the display settings. If you never changed it, the screen runs at 60Hz even though the input can do 144Hz.
• Driver or handshake limiting available modes — an outdated or generic GPU driver may only advertise 60Hz for this QHD resolution, or the monitor's EDID handshake fails over a poor-quality adapter, hiding the 144Hz modes from the OS.
• Wrong resolution selected first — some drivers only show 144Hz at the native 2560x1440; if the desktop is running a scaled/lower resolution or the monitor is in an odd signal mode, higher refresh options can disappear from the list.

How to Fix

1. Plug into the DisplayPort 1.4 input with a good cable — use the included (or a VESA-certified) DisplayPort cable into the DP port on the monitor and the matching output on your GPU. This is the only input guaranteed to carry the full 2560x1440 @ 144Hz FreeSync signal. Avoid USB-C and verify in the OSD Input menu that you are on the DP input.
2. Set 144Hz in Windows — right-click the desktop → Display settings → Advanced display, confirm the resolution is 2560 x 1440, then set the refresh rate dropdown to 144 Hz (apply and keep). On macOS, hold Option and choose 144Hz in the display refresh dropdown.
3. Confirm 144Hz in the OSD — press the joystick/remote, open the OSD System or Display info page and check the reported refresh rate says 144Hz (not 60Hz). If it still shows 60Hz, the connection or cable is the bottleneck from step 1.
4. Update the GPU driver — install the latest stable driver from AMD/NVIDIA/Intel so the driver advertises the 144Hz modes for the EX2780Q's EDID, then reopen Display settings and set 144Hz again.
5. Retry with a certified cable and reseat connections — if HDMI is the only option, switch to a proper HDMI 2.0 (18 Gbps) cable, not an old 1.4 one, reseat both ends, and re-select the input. A cheaper or damaged cable is the most common reason 144Hz stays greyed out.