The LG GX has okay peak brightness. It gets bright enough to combat glare in moderately-lit rooms, but it may not be good enough for a bright environment. Because of its aggressive Automatic Brightness Limiter (ABL), its brightness isn’t very consistent across different content and it quickly becomes dim with large, bright areas.
We measured peak brightness before calibration, although we normally take the results after calibration. This is because calibrating the TV significantly improved the 100% peak window up to 269 cd/m², while the other results only slightly improved by one or two nits. Since calibration changes per unit, not every TV would get brighter like ours, and some may get dimmer.
We measured the SDR peak brightness in the ‘Expert (Dark Room)’ Picture Mode with OLED Light at its max and Peak Brightness setting on ‘High’. We got the brightest image possible with these settings, as seen in the 10% peak window test.