Which is better for PS5 and Xbox Series X gaming?

The C5. It reaches 144Hz, adds G-Sync and FreeSync Premium, and has a Dolby Vision game mode. The C3 handles 4K/120Hz VRR well, but the C5 gives more headroom and smoother motion.

Is the C5 noticeably brighter than the C3?

Yes. The C5 uses an OLED evo panel with Brightness Booster, so highlights and full-screen scenes hold up better in a lit room. The C3 is still a strong dark-room TV.

Both are OLEDs with similar panel life. The C5 has the edge on software, with webOS 25 and up to five years of updates, so it stays current longer.

Do both support Dolby Vision and Dolby Atmos?

Yes. Both handle Dolby Vision, HDR10, and HLG, and both decode Dolby Atmos. The C3 also lists DTS:X support.

Is the C3 still worth choosing over the C5?

For a bedroom or secondary room where 120Hz and Wi-Fi 5 are enough, the C3 covers the basics well. For a main gaming or movie room, the C5's brighter panel and faster features are the better fit.

Which has better smart features?

The C5. It runs webOS 25, works with Alexa, Google Assistant, HomeKit, and Matter, and has Wi-Fi 6. The C3 runs an older webOS and lists Alexa and HomeKit only.

LG C5 OLED evo 4K Smart TV vs LG C3 48" OLED TV

Both are 48-inch LG OLEDs with the same core strengths: perfect blacks, wide viewing angles, Dolby Vision, and four HDMI 2.1 ports. The C5 is the newer, brighter, faster set, with a stronger processor, 144Hz gaming, Wi-Fi 6, and a longer update promise. The C3 is an older model that still looks excellent for movies and casual gaming, but it tops out at 120Hz, uses Wi-Fi 5, and has less headroom for future updates. Buy the C5 unless the C3's older design fits a secondary room or a tighter setup.

Choose the LG C5 if you want the brightest, smoothest 48-inch OLED for gaming and movies, with the longest software support.
Choose the LG OLED48C3PUA if you want a proven 48-inch OLED for film and light gaming and don't need 144Hz or the newest processor.

Prices

LG C5 OLED evo 4K Smart TV: $869.79 at Best Buy (checked today)