Monitor keeps going black for 2 seconds — real fix

You're in the middle of a game or just switching browser tabs — and bam, the monitor goes completely black for 1-3 seconds. Then it comes back like nothing happened. No error message, no crash, just a brief blackout. It's infuriating.

This usually happens under specific conditions: when the GPU is under load (gaming, rendering), when you change resolutions or refresh rates, or right after waking the PC from sleep. Some users only see it when the monitor uses G-Sync or FreeSync. Others report it happens once an hour like clockwork.

What's actually causing it

The root cause is almost always one of two things: a flaky cable connection or the GPU driver resetting itself. The driver reset is especially common with NVIDIA cards on version 5xx drivers when VRR (variable refresh rate) is enabled. The GPU briefly loses sync with the monitor, and the display goes black while the driver renegotiates the link.

Less common but still real: the monitor's power-saving features kicking in too aggressively, or the monitor's scaler chip getting confused by a signal switch. But 9 times out of 10, it's either the cable or the driver.

Skip the Windows power plan tweaks — they rarely fix this. Same goes for reinstalling the monitor driver. Waste of time.

The fix — step by step

1. Replace the cable. Not just re-seat it — swap it. HDMI and DisplayPort cables degrade, especially if they're cheap or older than 3 years. Use a certified DisplayPort 1.4 or HDMI 2.1 cable. Don't use a cable longer than 3 meters (10 feet) for 4K 144Hz. Shorter is better.
2. Turn off VRR/G-Sync/FreeSync temporarily. Go into NVIDIA Control Panel or AMD Adrenalin, disable G-Sync or FreeSync. If the blackouts stop immediately, that's your culprit. If you need VRR (for gaming), then update the monitor's firmware if available (yes, monitors have firmware — check the manufacturer's support page).
3. Change the refresh rate to a standard value. Set it to 60Hz first. If the blackouts stop, then step up to 120Hz or 144Hz. Some monitors have flaky EDID data that causes the GPU to drop sync at non-standard refresh rates (e.g., 100Hz on some LG panels).
4. Disable the monitor's deep sleep or power saving. Open the monitor's on-screen display (OSD) menu. Look for settings called: "Power Saving", "Deep Sleep", "Eco Mode", or "Auto Power Off". Disable them. This stops the monitor from going into a low-power state that can cause signal loss when the GPU sends a brief idle signal.
5. Update GPU drivers — but do a clean install. Download the latest driver from NVIDIA or AMD, but when installing, select "Custom (Advanced)" and check "Perform a clean installation." This wipes old driver remnants that can cause timing conflicts.

If it still fails

Try a different port on both the GPU and the monitor. Some monitors have one DP 1.4 port and one DP 1.2 port — use the 1.4 port. On the GPU side, avoid daisy-chained monitors or multi-monitor setups with mixed refresh rates (60Hz + 144Hz) without enabling "Multi-monitor power saving" in the driver — that setting causes exactly this issue.

Test the monitor on another PC. If the blackout happens there too, the monitor's mainboard or power supply is dying. At that point, it's replacement time — repair cost usually isn't worth it.

I've seen this exact issue on ASUS VG27AQ, Dell S2721QS, LG 27GP850, and Samsung Odyssey G7. In every case, swapping the DisplayPort cable to a shorter, certified one fixed it. Don't overthink this — start with the cable.