LG OLED HDMI Setup: Best Ports & Settings for 4K HDR Gaming

LG OLEDs (C-series and G-series) are a gaming benchmark for one reason: all four HDMI ports are full HDMI 2.1 at 48 Gbps — unlike most TVs, where only one or two ports do 4K@120Hz. So on an LG OLED the question isn't "which port is fast enough," it's which port to use given eARC, and which settings actually turn on 4K120/VRR/G-Sync. Here's the setup.

Which port to use

• Any HDMI 1–4 does 4K@120Hz, VRR, and G-Sync on C/G-series OLEDs — they're all 2.1.
• HDMI 2 is the eARC port. If you run audio out to a soundbar over eARC, keep that on HDMI 2 and put your consoles on the others — so you're not fighting for the eARC port.
• Best practice: console(s) on HDMI 1/3/4, soundbar/receiver on HDMI 2 (eARC).

Settings that unlock gaming

1. Enable HDMI Deep Color for the port. Settings > General > Devices > HDMI Settings > HDMI Deep Color = On for the input in use. Without it the port runs a 4K@60Hz-limited mode and 120Hz/4K HDR won't appear — this is the #1 missed setting, and the same one behind most LG OLED "No Signal" / no 4K HDR complaints.
2. Turn on Game Optimizer / Game Mode. It drops input lag to ~10ms and exposes VRR/ALLM. The Game Optimizer menu (gear during gaming) has VRR, black stabilizer, and the genre presets.
3. VRR / G-Sync / FreeSync live under Game Optimizer > VRR — enable for tear-free 120Hz. LG OLEDs are both G-Sync Compatible and FreeSync Premium.
4. Use a certified Ultra High Speed (48 Gbps) cable. Even with all ports at 2.1, a cable that can't carry 48 Gbps caps you at 4K60 or causes 120Hz black-screen flicker.

Per-source quick notes

• PS5: Settings > Screen and Video > set Resolution Automatic, enable 120Hz and VRR. The PS5 supports 4K@120Hz on select titles; if you hit random black flashes, the PS5 + LG C2/C3 VRR setup clears them.
• Xbox Series X: 4K TV details should report 4K120 + VRR once Deep Color is on. (Series S renders games at 1440p, not 4K.)
• PC: select G-Sync in the NVIDIA panel; the OLED reports as G-Sync Compatible.

FAQ

Which HDMI port is best for gaming on an LG OLED? Any of HDMI 1–4 — they're all full 2.1 (48 Gbps). Just keep your soundbar/receiver on HDMI 2 (the eARC port) and consoles on the others.

I'm not getting 120Hz on my LG OLED. Turn on HDMI Deep Color for that input (General > Devices > HDMI Settings) and use a certified 48 Gbps cable — without Deep Color the port is capped at 4K60.

Does the LG OLED support G-Sync? Yes — it's G-Sync Compatible and FreeSync Premium. Enable VRR in the Game Optimizer menu.

Which port is eARC? HDMI 2 on C/G-series OLEDs. Use it for your soundbar/receiver audio return.