Causes
- G-Sync Compatible / FreeSync Premium variable-refresh flicker — the VG27AQ is certified G-Sync Compatible and FreeSync Premium but uses a standard Adaptive-Sync-scaler panel (no dedicated G-Sync hardware module). On this kind of panel the backlight can visibly flicker or pulse when the in-game frame rate swings rapidly, especially near the bottom of the variable range or when it jumps between very high and very low FPS. This is the single most-reported VG27AQ flicker, and it usually appears over DisplayPort rather than HDMI.
- The 165Hz overclock outrunning a weak or worn DisplayPort 1.2 cable — the VG27AQ is natively a 144Hz panel whose 165Hz mode is an overclock enabled in the OSD. Pushing 2560x1440 past 144Hz at 8-bit color over an uncertified, long, kinked, or poorly shielded DP cable pushes the DP 1.2 link very near its bandwidth ceiling, and the signal degrades into intermittent flicker or brief dropouts. Many owners only see flicker at 165Hz and it vanishes at 144Hz.
- ELMB Sync conflicting with adaptive sync — the VG27AQ's ELMB Sync combines backlight strobing (motion-blur reduction) with adaptive sync. When ELMB/ELMB Sync is left enabled, the strobed backlight itself produces a visible flicker or banding on bright scenes, and it can fight the VRR engine, producing a shimmer that many mistake for a hardware fault.
- Bad or outdated GPU drivers plus overlay apps — flicker is frequently triggered by an outdated or freshly broken graphics driver, or by real-time overlay tools (MSI Afterburner/RivaTuner, RGB or GeForce overlay) forcing the desktop to resync at odd intervals. A GPU driver crash that silently recovers (TDR) also reads as a one-second flicker.
- A DisplayPort connector that is almost, but not fully, seated — the VG27AQ's DisplayPort jack has a latch that needs the cable pushed in until it clicks. A half-seated connector loses pin contact on movement and flickers or blinks, especially at high bandwidth. The same happens with adapters (mini-DP or USB-C dongles) that are not firmly plugged in.
How to Fix
- Reseat the cable and swap to a certified DisplayPort cable — power the monitor off, unplug the cable from both ends, check for bent pins, and push the DisplayPort connector back in until it clicks into the latch. Replace any long, thin, or unbranded cable with a VESA-certified DP 1.2 or DP 1.4 cable (shorter is more reliable). If you are using an adapter or dongle, plug it in firmly at both the GPU and the adapter. Test the second DisplayPort/HDMI input on the VG27AQ to rule out a bad port.
- Turn off the 165Hz overclock and run at 144Hz — press the monitor's menu button, open the Setup or System menu, disable the 165Hz overclock, and set the refresh rate to 144Hz (in Windows: Settings → System → Display → Advanced display; or in the NVIDIA control panel). If the flicker stops at 144Hz but returns at 165Hz, the 165Hz OC was the cause and you can leave it disabled or switch to a higher-grade DP cable to make it stable. This is the fix that resolves the majority of VG27AQ flicker reports.
- Toggle G-Sync and ELMB Sync off to isolate VRR flicker — in the NVIDIA control panel set G-Sync to Off (or disable FreeSync in the OSD's Gaming menu), then in-game check whether the flicker stops while the frame rate fluctuates. If it does, VRR was the cause: you can re-enable it and instead cap the frame rate to a stable value close to the refresh rate (for example cap to 140 FPS at 144Hz), or leave adaptive sync off. Also open the OSD and turn ELMB Sync to Off — its backlight strobe is a direct source of visible flicker on bright scenes.
- Update or cleanly reinstall the GPU driver and close overlays — update to the latest stable driver for your graphics card. If flicker persists, remove the driver with Display Driver Uninstaller (DDU) in Safe Mode and reinstall fresh. Then close overlay apps (MSI Afterburner, RGB control, GeForce overlay, screen-recording tools) one at a time to find the one forcing the flicker.
- Power-cycle the monitor and reset the OSD — unplug the VG27AQ from the wall for 30 seconds and plug it back in. From the OSD menu choose the reset/factory-default option to clear any stuck overclock, ECO, or color profile. If flicker only occurs when Adaptive-Sync is combined with ELMB Sync, resolve by never enabling both at the same time.