The Dell UltraSharp U4025QW runs with the Mac Studio M1 Ultra, 128 GB, but macOS does not support 120 Hz refresh rate on M1 and M2-based Apple devices with this monitor. The maximum refresh rate on Apple Silicon devices is usually 60 Hz for 5K2K resolution, as 120 Hz support is limited by the M1/M2 architecture. There are reports that the frequency can be increased to around 100-110 Hz with special configurations, but this is not activated by default and requires manual adjustments. Full 120 Hz utilisation is therefore not possible without further ado.

The monitor offers a 5K2K resolution (5120 x 2160 pixels) and is well connected to the Mac Studio via Thunderbolt 4, which enables a clean and powerful connection. Colour accuracy and connectivity are well suited to Mac users, although there are limitations with the volume control of the integrated speakers under macOS.

To summarise: The monitor works with the Mac Studio M1 Ultra, but the 120 Hz refresh rate is not supported by macOS on M1, the refresh rate is limited to 60 Hz.