I spent a few evenings tearing down the settings on my LG UltraGear 27GP850 to answer a question I kept seeing in forums and DMs: will lowering G-Sync and display overdrive cut input jitter at 240 Hz? As someone who chases both buttery motion and rock-solid aim, this one’s personal — jitter can feel like a soft, invisible handicap. Below I walk through what I tested, what actually changes when you tweak G-Sync and overdrive (a.k.a. response time), and practical settings that balanced smoothness, latency, and artifacting on this specific panel.
What people mean by "input jitter"
First, let’s align terms. When players say input jitter they often describe small, inconsistent cursor or crosshair movement that looks like micro-stuttering. That sensation can come from several sources:
Frame pacing issues between GPU and display (VRR / G-Sync behavior)Panel pixel response inconsistency or overshoot from aggressive overdriveSoftware/driver polling jitter (mouse, USB stack)Measurement noise vs perceived jitter in the human eyeOn the 27GP850 at 240 Hz, the two suspects most within reach of changing in the OSD and drivers are G-Sync/VRR handling and the monitor's overdrive setting. That's what I focused on.
How I tested — tools and methodology
I wanted practical, repeatable checks rather than just subjective impressions. My test bench:
PC with an NVIDIA GPU (drivers up to date)LG UltraGear 27GP850, firmware currentMouse: wired gaming mouse at 1000 Hz, consistent pollingTools: Blur Busters Video Settings and Frame Skipping tests, NVIDIA Control Panel, and in-game tests using a consistent sensitivity/aim-train scenarioOptional: capture card + high-speed camera for frame timing / visual confirmationTests performed:
Toggle G-Sync On/Off (NVIDIA Control Panel) at 240 Hz, run blur tests and aim practice, look for micro-stutter.Cycle overdrive (Response Time) settings in OSD: Off, Normal, Fast. Note overshoot artifacts and perceived jitter.Combine settings (G-Sync On + Overdrive Normal, G-Sync Off + Overdrive Fast, etc.) and run identical scenarios.Record observations about perceived micro-stutter, visible ghosting, and any oscillatory behavior of the crosshair.What I observed
Short version: lowering overdrive reduced visible overshoot and improved perceived smoothness in many cases; toggling G-Sync had mixed results depending on framerate stability. Details:
Overdrive: Off vs Normal vs Fast: Fast reduces pixel transition time but introduces overshoot (inverse ghosting) which can be perceived as jittery or "twitchy" edges during rapid camera moves. On the 27GP850, Fast at 240 Hz produced the cleanest motion blur reduction but sometimes added thin, bright trailing artifacts on high-contrast edges — those artifacts can trick your eyes into thinking the pointer is unstable. Normal provided a good middle ground with much less overshoot and still decent crispness. Off removed overshoot but left more smear, which some players interpret as motion lag.G-Sync/VRR: When framerates stayed close to 240 FPS, G-Sync maintained smoothness and I didn’t notice additional jitter. When framerates fluctuated a lot (e.g., CPU-limited scenarios or background processes), G-Sync sometimes produced micro-stutter as it tried to match the refresh window. In those cases, turning G-Sync off and letting the monitor run at a fixed 240 Hz with triple buffering sometimes felt smoother because the GPU was delivering more consistent frame pacing at a high fixed rate.Combination effects: The worst offender for perceived jitter on my unit was the combo of aggressive overdrive (Fast) with framerate fluctuation under G-Sync. Overshoot gives the eye a phantom double-edge during rapid movement, and the dynamic timing of VRR can make that ghosting look like inconsistent crosshair movement. Lowering overdrive to Normal while keeping G-Sync On removed most of that phantom jitter while maintaining low latency.Practical settings I recommend for the 27GP850 at 240 Hz
Based on the tests above, here are settings I use and recommend depending on your priorities:
| Priority | Overdrive (OSD) | G-Sync/VRR | Why |
| Competitive low-latency, stable framerate (~240 FPS) | Normal | On | Best balance: low pixel smear, minimal overshoot, and VRR smoothing at stable FPS |
| Competitive, inconsistent FPS | Normal | Off (240 Hz fixed) + triple buffering | Eliminates VRR timing quirks that can amplify perceived jitter |
| Single-player visual fidelity | Off | On | Smoother appearance for cinematic motion, no overshoot artifacts |
| Max motion clarity (risking artifacts) | Fast | On | Sharpest transitions but watch for overshoot-induced phantom jitter |
Additional checks and tips
Lowering overdrive helped reduce one form of perceived jitter on my unit, but it’s not a universal fix. A few more things to check:
Make sure your mouse polling and USB drivers are stable — jitter can be input-side, not display-side.Use consistent framerate targeters (e.g., in-game FPS cap slightly below 240 if you want to avoid VRR windowing issues) — surprising smoothness gains come from more stable frame delivery.Turn off post-processing motion smoothing or any "motion interpolation" features — these add latency and can introduce micro artifacts.Consider testing with a high-speed camera or a motion test (Blur Busters UFO, hand-captured) if you want objective proof of pixel response changes.My bottom line after testing
On the LG 27GP850 at 240 Hz, lowering aggressive overdrive settings usually reduces overshoot that can be interpreted as input jitter. G-Sync itself is generally beneficial when you hold a steady high framerate, but if your system is delivering inconsistent FPS, VRR timing can interact with overdrive artifacts and make jitter worse. For most competitive scenarios I landed on Overdrive = Normal and G-Sync = On as the best practical compromise — or G-Sync Off if I can't keep my FPS steady near 240.
