NVIDIA has announced that it is bringing G-Sync to non-G-Sync branded variable refresh rate (VRR) monitors. Incidentally, the company has started by certifying 12 AMD FreeSync monitors as being "G-Sync Compatible", but it will continue to test and certify other displays, according to a press release.
NVIDIA has also elaborated on how it will test monitors for G-Sync compatibility. The same press release stated that a monitor would only be certified as being G-Sync Compatible if it:
does not show blanking, pulsing, flickering, ghosting or other artifacts during VRR gaming.
The monitor must also support a VRR range of at least 2.4:1, which corresponds to between 60 Hz and 144 Hz. Displays certified as G-Sync Compatible will have the functionality turned on by default but fear not if you have a non-certified monitor as NVIDIA is adding a new NVIDIA Control Panel option to enable G-Sync manually. The functionality will only work with a GTX 10 series or RTX 20 series GPU though.
Essentially, NVIDIA has split G-Sync into three tiers as the image below demonstrates. The top level is now known as G-Sync Ultimate, which is a rebranding of G-Sync HDR. G-Sync Ultimate certification will be reserved for those displays that are also branded as Big Format Game Displays (BFGD). The first BFGD display is the HP OMEN X Emperium 65, which is a 65-inch 4K HDR monitor that can reach up to 1000 nits and has an integrated NVIDIA Shield. There is some confusion about the refresh rate though as NVIDIA claims that it is 120 Hz, but HP lists the OMEN X as having a 144 Hz refresh rate. Both companies state that the monitor is available to pre-order on Amazon US, but it is listed as currently unavailable at the time of writing.