HDMI connected Samsung Monitor says "Not Optimum Mode, Recommended Mode 1920x1080 60 hz"

I have 5 Syncmaster monitors and I have found this issue very troubling with 3 out of 5. I found some partial solutions and or workarounds. The workaround solution of hitting the Menu or OCR button on the side or bottom right of the monitor for an instant, shuts the Optimum Resolution message off until the next time you turn it on. This is an issue with all the Syncmaster models newer than b2030.

Syncmaster 2033 has the problem when using a DVI to VGA adapter on the PC and a VGA cable from adapter to monitor, occurring every time you turn monitor on or bring it out of sleep regardless of what the resolution is set at. With a DVI to DVI or VGA to VGA it only reports Optimum Resolution notice if you exceed the optimum resolution. The OS, GPU, or HDMI cable are not related to this, except for the HDMI cable which must be a special high speed designation for 4K display or will not do 2160p.

Syncmaster b2030 only displays optimum resolution notice if you exceed the optimum resolution. This model works with all connector configurations, IE: DVI to DVI, VGA to VGA, HDMI to HDMI, And DVI to VGA Adapter and VGA from adapter to monitor.

Syncmaster B1940 never displays the optimal resolution notice including when you exceed the max resolution of both the monitor and GPU by creating a custom resolution. I tried all the way to 1920 by 1080 successfully without Optimum resolution notice (monitor and GPU only can go to 1280 x 1024 max).

I did notice variations in my DVI cables, even though they all had the same logo markings. One DVI had 3 rows of pins and a flat blade pin on one side. The second DVI cable had 2 sets of 3 rows with the middle 2 columns of pins missing and a flat blade pin on one side. The third DVI cable had 3 rows of pins with a flat blade pin on one side with 4 pins boxing in the flat blade pin. The fourth DVI connector was an antique with 4 rows of pins and no flat blade connector. Additionally, I seem to remember a DVI connector I had with 3 rows of pins and 2 flat blade pins at 90 degrees from each other.

The problem seems to be due to how different Syncmaster monitors handle the slightly modified communication due to use of DVI to VGA adapter.

Specifically, My DVI to VGA adapter has the 3 rows of pins with the one side blade pin boxed in by 4 pins. The DVI to DVI cables I have, are missing either the 4 pins that box the blade pin or they are missing the center 2 columns of pins and the 4 pins that box the blade pin.

I tested the theory of a possible fix, that would only be available to a PC with a GPU control app like NVIDIA Control Panel or AMD Radeon software that allows creation of custom resolutions and especially Option to change scaling from application to GPU usually under the HDMI or Flat monitor options.

Using AMD Radeon software I went into Home then select the settings gear icon and then select display and then disable GPU scaling. When I have GPU scaling on I get the Optimal Resolution notice right away and again every time I start the monitor or come out of sleep even if the resolution is correct. When I have GPU scaling off I only get the Optimal Resolution notice if I exceed the optimal resolution.

Using Nvidia Control Panel You go to display and then set display size and position and then select Use the following settings select scaling and then select none for scaling mode and select desktop for scaling to stop the optimal resolution notice.