Out of Range

LG 27GL850 'Out of Range' at 144Hz 10-Bit — The Real Fix

EP
Erropedia Team
📅 September 11, 2026 📅 Updated Sep 12, 2026 👁 4 views Hardware – Monitors Intermediate
Your LG 27GL850 says 'Out of Range' when you pick 10-bit color at 144Hz over DisplayPort. Drop it to 8-bit, or drop refresh to 120Hz — the DP 1.2 link can't carry both.

You bought a 144Hz 1440p monitor, enabled 10-bit color for HDR, and now the screen flashes "Out of Range" like it's 2007 and you're feeding a CRT the wrong refresh rate. Annoying, and the fix is more boring than you'd hope.

The Fix

You've got two options. Pick one based on what you actually need.

Option 1: Drop to 8-bit (keeps 144Hz)

  1. Right-click the desktop, open NVIDIA Control Panel (or AMD Software if you're on Radeon).
  2. Go to Change resolution.
  3. Make sure the LG 27GL850 is selected, refresh rate is set to 144Hz.
  4. Scroll down to Output color depth and set it to 8 bpc.
  5. Hit Apply. The monitor should recover within a couple of seconds.

On AMD cards it's under Display > Color Depth. Same idea.

Option 2: Keep 10-bit, drop to 120Hz

  1. Same NVIDIA Control Panel, same Change resolution page.
  2. Set refresh rate to 120 Hz.
  3. Set output color depth to 10 bpc.
  4. Set output color format to RGB (not YCbCr 4:2:2 — you don't want chroma subsampling at a desk).
  5. Apply.

If the monitor is already stuck on "Out of Range" and you can't even see the desktop, boot into Safe Mode. Windows drops the resolution to 1024x768 and lets you get in, then revert the settings from there.

Had a client last month — video editor, LG 27GL850, Ryzen 9 + RTX 4070 — who spent two days thinking his GPU was dying. Nope. He'd ticked 10-bit at 144Hz in the control panel and the monitor just refused to lock onto the signal.

Why It Actually Happens

The 27GL850 is a DisplayPort 1.2 monitor. Not 1.4. Not 2.1. 1.2. That gives you 21.6 Gbps of raw bandwidth, and after 8b/10b encoding overhead you're working with about 17.28 Gbps usable.

Now do the math for 2560x1440 at 144Hz with 10-bit RGB:

  • Pixels per second: 2560 x 1440 x 144 = 530,841,600
  • Bits per pixel at 10-bit RGB: 30
  • Total: ~15.9 Gbps of pure pixel data
  • Add CVT-RB blanking intervals and you're north of 17.5 Gbps

You're over budget. The GPU negotiates a mode the monitor can't lock, and the scaler throws "Out of Range" because it has no valid timing to sync to. LG's spec sheet lists 144Hz and 10-bit separately — they don't advertise that you can't run both at once over DP 1.2. That's the trap.

Drop to 8-bit RGB at 144Hz: 2560 x 1440 x 144 x 24 = ~12.7 Gbps. Comfortably fits. Drop to 120Hz at 10-bit: 2560 x 1440 x 120 x 30 = ~13.3 Gbps. Also fits. Both work, and that's not a coincidence.

Less Common Variations

You're on HDMI and getting the same error

Worse. The 27GL850's HDMI ports are 2.0 — 18 Gbps raw, ~14.4 Gbps usable. At 1440p/144Hz you're stuck at 8-bit 4:2:2 chroma, and 10-bit isn't happening at 144Hz no matter what you do. Use DisplayPort. If you must use HDMI, you're capped at 100Hz for 10-bit RGB.

DSC-supporting GPUs (RTX 20-series and newer, RX 5000 and newer)

Display Stream Compression should theoretically let you push 10-bit 144Hz through a DP 1.2 link. But the 27GL850 doesn't support DSC — the monitor side has to support it too, and this panel doesn't. Don't go hunting for a DSC toggle. It's not there.

Firmware and EDID weirdness

Early 27GL850 units shipped with an EDID block that misreported supported modes. If you've tried 8-bit at 144Hz and still get "Out of Range," check LG's support page for a firmware update for your specific revision. The fix is a Windows-only utility that flashes the monitor over USB — yes, really. Rare, but it exists.

Bad cable

Cheap Amazon DisplayPort cables that claim "4K 144Hz" but aren't VESA-certified will negotiate the wrong link rate. The monitor sees a 144Hz signal but the cable can't carry it, and you get the same error. Swap for a VESA-certified DP 1.4 cable — the cable matters even though the monitor is 1.2.

Windows HDR toggling it back on

Windows 11 sometimes re-asserts 10-bit color when you toggle HDR in Display settings, overriding your NVIDIA Control Panel selection. If the error keeps coming back after a reboot, turn HDR off in Windows Settings first, then set color depth in the control panel. Order matters.

Stop It From Happening Again

  • Leave 10-bit off unless you actually need it. For gaming, 8-bit is fine. For photo and video work, drop to 120Hz and enjoy the extra color depth — 24Hz isn't worth giving up 10-bit if color accuracy is the point.
  • Use a VESA-certified DP 1.4 cable. The monitor is 1.2, but a good cable removes one variable.
  • Don't let Windows HDR auto-toggle. Set it manually and remember it can reset color depth.
  • Save a working profile. NVIDIA lets you export color settings. AMD's got similar. Keep a known-good config so a bad toggle doesn't lock you out of your desktop.

The 27GL850 is a great panel. It's just a DP 1.2 panel dressed up in 144Hz marketing, and 10-bit at 144Hz is the one combo it can't do. Pick one, move on, get back to work.

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EP
Erropedia Team
Tech Support Editors
The Erropedia editorial team researches and documents real-world tech errors from across Windows, Linux, macOS, networking, databases, cloud platforms, and more. Every solution is reviewed for accuracy and updated as software and systems evolve.