Hi , Thank you for reaching out! My name is Stefano and it’s my pleasure to assist you today.
What you’re seeing is generally normal Windows/display-driver behavior, rather than evidence that the RTX 5060 or Gigabyte G27U cannot operate at 160 Hz.
Windows does not treat refresh rate as one global setting that must remain fixed when resolution changes. A display mode is effectively a combination of resolution + refresh rate + timing/format parameters.
When you switch from 3840×2160 to 1920×1080, Windows/your NVIDIA driver selects a new display mode, and that mode can default to 60 Hz. Returning to 4K does not necessarily restore the previously selected 160-Hz mode.
So, unfortunately, the expectation that selecting 160 Hz once should force every subsequently selected resolution to use 160 Hz isn't how Windows currently guarantees mode switching.
So, what you've to do si re-apply the Refresh Rate in Windows Settings
- Right-click your desktop and select Display settings.
- Scroll down and click Advanced display (or Advanced display settings).
- Under the Refresh rate dropdown menu, select 160 Hz again
Please, see the microsoft support article below:
Thing worth trying, lock the Refresh Rate in Your GPU Control Panel
Be sure you've installed the most updated NVIDIA drivers.
Acces the NVIDIA Control Panel > Display > Change resolution
For each resolution you actually use, select the resolution and explicitly choose 160 Hz under Refresh rate, then click Apply.
Pay particular attention to the resolution list. NVIDIA Control Panel can show resolutions in separate groups such as Ultra HD, HD, SD and PC. If 1920×1080 is available under PC, try that version and select 160 Hz. Different entries can correspond to different timing modes, and the TV-style entries often favor 60 Hz.
Kind regards,
Stefano