G-Sync technology appeared earlier than similar AMD FreeSync technology and initially meant equipping monitors with special proprietary hardware. At the same time, similar technology from AMD did not require the use of additional equipment in monitors and therefore quickly gained popularity among manufacturers and consumers. As a result, NVIDIA had to be more flexible about integrating G-Sync support. It offered three types of its technology: G-Sync Compatible (compatible with G-Sync without the presence of special hardware), support for G-Sync (the monitor is equipped with an NVIDIA module), and full support for G-Sync Ultimate (similar to the previous one, only for monitors with HDR support).

For G-Sync Ultimate, the company has set specific requirements. For example, back at CES 2019, the company announced the following required specifications for monitors with G-Sync Ultimate support:

• The brightness of the display is above 1000 cd / m ² ;
• Support for high resolution and refresh rate;
• The fast response of the matrix;
• Multi-zone illumination;
• Wide colour space coverage;
• Equipped with an advanced NVIDIA G-Sync processor;

However, at CES 2021, when it was announced that three new monitors had passed the G-Sync Ultimate certification, it turned out that two of them did not meet the original requirements – they did not have the VESA DisplayHDR 1000 certification. However, they did have the VESA DisplayHDR 600 certification. , but this conflicts with early NVIDIA requirements for the G-Sync Ultimate standard.

Moreover, the changes were found on the NVIDIA website in the G-Sync section. Manufacturer removed references to the brightness of 1000 cd / m ², and instead pointed to the display as a requirement for support “realistic HDR». In other words, now the support of G-Sync Ultimate does not mean brightness display higher than 1000 cd / m ².