Backlight strobing (ULMB / motion blur reduction)
Also searched as: ulmb · backlight strobing · motion blur reduction · mbr · elmb · dyac · black frame insertion · bfi · strobing · blur reduction
What it means
Backlight strobing — sold as ULMB, ELMB, DyAc, or just 'motion blur reduction' — flashes the monitor's backlight off between frames so each frame is shown for less time. That cuts the natural blur you get on modern (sample-and-hold) LCD and OLED panels, making fast motion look sharper, closer to an old CRT.
More detail
The catches are real. It usually cannot run at the same time as VRR (G-Sync / FreeSync) — most monitors make you pick one or the other — so you trade tear-free smoothness for motion clarity. …
In the Blackbook
The deeper explanation continues inside the app. The Blackbook publishes its verdicts here — the full write-ups stay in the book, on your rig, next to your own measurements.
The Compy Blackbook holds 191 graded entries like this one, judged against your hardware — and every change it does make is reversible, with the receipt to prove it.
See Compy →