Most monitors work fine for all membership types. To unlock HDR benefits with the Ultimate membership tier, you must use a monitor that supports the HDR10 format.
Recommended for GeForce NOW Ultimate Membership
Ultimate Members can enjoy up to 3840x2160, 3840x1440, 2560x1440, 3840x1600 and 2560x1600 resolutions. 120 FPS streaming will require a monitor that supports at least 120Hz, such as NVIDIA G-Sync Monitors or a MacBook Pro 14” or 16” with ProMotion 120Hz refresh rate. 240 FPS streaming will require a monitor that supports at least 240Hz. You must connect to the monitor using an HDMI, Mini DisplayPort, Thunderbolt 1/2/3, USB-C, or USB 4 connector. Your system may require an additional adapter, or cable, to connect to the monitor. Any adapter used must support DisplayPort 1.2 or HDMI 2.0. Please read this knowledge base article for more information.