I’m trying to get 4K120/144, but macOS offers only 60 Hz at 4K, despite receiving EDID data advertising 4K120.
Setup
-
Mac: MacBook Air 15″ (2024), M3, 10-core GPU, 16 GB RAM, model
Mac15,13; macOS 26.6.2 (25G83). -
Adapter: Club3D CAC-2505, USB-C DP 1.4 Alt Mode → HDMI 2.1; Synaptics VMM7100, USB VID
06CB:7100; firmware version unknown. - HDMI cable: Club3D CAC-1372, 2 m, certified Ultra High Speed HDMI 2.1, 48 Gbps, rated for 4K120/8K60.
-
TV: LG OLED65CS6VA, 65″ 4K OLED, up to 144 Hz; detected as
LG TV SSCR2. -
Connection: Mac → adapter → HDMI cable → TV. Built-in display active; mirroring off.
Tests: Enabled Game Optimizer and 144Hz mode; disabled macOS HDR; unplugged/reconnected and tested both USB-C ports. Identical results. Clamshell and same-cable/port PS5 4K120 tests not performed.
Diagnostic excerpts / summary
system_profiler:
LG TV SSCR2
Resolution: 3840 x 2160
UI Looks like: 1920 x 1080 @ 60.00Hz
Mirror: Off
CoreGraphics CGDisplayCopyAllDisplayModes
(including duplicate low-resolution modes):
215 modes
3840x2160: 24, 25, 30, 50, 60 Hz
2560x1440: includes 120, 144 Hz
1920x1080: includes 100, 120, 144 Hz
No 4K120/144 modes, including unscaled 4K.
ioreg:
BranchDeviceID: SYNAq
LinkRateDescription: 8.1 Gbps (HBR3)
LaneCount: 4
MaxLaneCount: 4
EDID includes CTA VIC 118 (3840x2160 @ 120 Hz).TV VRR information, captured with HDR enabled:
60.0Hz
FIXED
3840 x 2160P@60
YCBCR422 8b 4L6 HDR10 FVA:1Has anyone achieved 4K120/144 with this adapter on an M3 Mac under Tahoe? Is specific CAC-2505 firmware required, or is there another diagnostic/settings change to try?
