Which is better for gaming, the C5 or the C6?

The C6. It reaches 165Hz VRR and adds G-Sync, FreeSync and QFT on top of the C5's 144Hz ceiling. Both give you four HDMI 2.1 ports at 4K 120Hz.

Is the C6 worth stepping up to over the C5?

Yes if you want the newer Alpha 11 processor, more gaming headroom and better built-in sound. The C5 remains a strong set, and its Wi-Fi 6E is the one spec where it beats the C6.

Which has better built-in sound?

The C6, with a 2.2-channel 40W system. The C5 uses a 2-channel setup with Dolby Atmos and a9 AI Sound Pro. Either benefits from a soundbar for serious movie watching.

Do both support Dolby Vision and Dolby Atmos?

Yes. Both are OLED evo 4K sets with Dolby Vision, HDR10 and HLG, and both decode Dolby Atmos.

Neither has a published lifespan edge. The C6 is a year newer, so it should receive webOS updates for longer. LG OLED panels have a strong reliability record across both series.

Will either fit a wall mount easily?

The C5 is 1.9 inches deep without its stand, which suits a flush wall mount. The C6 measures 10.5 inches deep with its stand, so check clearance if you keep it on furniture.

LG C5 OLED evo 4K TV vs LG C6 OLED 77" 4K Smart TV

Both are 77-inch LG OLED evo sets with perfect blacks and four HDMI 2.1 ports; the C6 is the newer 2026 model with the stronger Alpha 11 processor, 165Hz VRR and 40W of sound, while the C5 is the well-proven 2025 set with the Alpha 9 Gen8 chip and Wi-Fi 6E. Buy the C6 if you want the longest useful life and the best gaming headroom; buy the C5 if you want a known quantity and its Wi-Fi 6E is more useful to you than the C6's newer silicon. Owners of both praise color accuracy and the 77-inch scale for movie nights; the C6's 4.7 rating from 204 buyers is solid, and the C5 line has a strong multi-year track record.

Choose the LG C5 if you want a proven 2025 OLED with Wi-Fi 6E and the Alpha 9 Gen8 processor, and you would rather not pay for the newest chip.
Choose the LG C6 if you want the newest panel generation, the Alpha 11 processor, 165Hz VRR and stronger built-in sound.

Prices

LG C5 OLED evo 4K TV: $1,796.95 at Amazon (checked today)