Causes
- Overdrive set to its fastest 'Faster' setting — the 27GP850-B's Response Time menu pushes the Nano IPS pixels hard to reach its 1ms claim. At the Faster level the panel over-draws each transition, causing inverse ghosting — a bright white or colored trailing edge behind moving objects. Owners report "terrible ghosting" that persists no matter what else is changed, which in most cases traces straight back to this setting.
- Overdrive too aggressive for the actual refresh rate — LG advertises variable overdrive, but with VRR (G-Sync Compatible / FreeSync) the frame rate swings, and the overdrive can't track it: at lower frame rates the same fast overdrive overshoots more, so trails appear during dips in fps even when the overdrive is reasonable at 165Hz.
- A 60Hz or low refresh source through fast overdrive — when the monitor is driven at 60Hz (console, low-Hz content, or a cable that can't reach 165Hz), the pixel transitions have far more time to overshoot, so the same faster overdrive visibly smears and ghosts even though it was clean at high refresh.
- Backlight strobing (Motion Blur Reduction / BFI) enabled — the 27GP850-B's backlight strobing feature cuts persistence blur but can introduce flicker-like artifacts and crosstalk double-images, particularly at lower strobe frequencies, which users mistake for ghosting.
- GPU driver or refresh mismatch — a driver that forces an odd refresh or color-depth cycle while VRR is on can make fast motion look smeary/ghosted even at otherwise healthy settings.
How to Fix
- Lower the Response Time / overdrive in the OSD — open the Game Adjust menu and set Response Time from Faster down to Fast (or Normal). This is the most effective single fix — the fastest setting exists to chase the 1ms spec and over-shoots on most units. Keep Faster only if you still see no trails at your refresh rate.
- Run the monitor at its native 165Hz (or 180Hz OC) — in Windows go to Settings → System → Display → Advanced display and set the 27GP850-B to 165Hz at 2560x1440 (180Hz if you've enabled the Overclock in the OSD). Running it at 60Hz or a mismatched rate makes any overdrive ghost because the pixels overshoot. Check that your DisplayPort cable supports the bandwidth for the faster setting.
- Sort out variable refresh — if you use G-Sync Compatible / FreeSync, keep the overdrive on Fast or Normal and cap the in-game frame rate at a stable value (for example ~140 fps at 144–165Hz) so the frame rate doesn't swing into the range where overdrive overshoots. If trails only appear during VRR dips, a stable cap resolves it.
- Disable backlight strobing — if you have Motion Blur Reduction or the strobing/1ms mode on in the OSD, turn it Off and see if the ghost/double-image disappears. Strobing trades persistence blur for crosstalk artifacts and is a common source of perceived ghosting on this model.
- Update or cleanly reinstall the GPU driver — install the latest stable driver (use Display Driver Uninstaller in Safe Mode if trails persist), since a refresh/VRR handling conflict can smear fast motion.
- If nothing clears it, test on another device and get support — connect a known-good cable from another GPU or laptop. If ghosting/inverse ghosting still appears across overdrive levels, refresh rates, and devices, the panel's response-time controller may be faulty and the monitor should be serviced under warranty.