There is a facility to Export the EDID of the monitors in SwitchResX, I did this on one of the older monitors and the new one. I'm not sure if this might help solve the issue or not, but here is a copy+paste of the files:
Old Monitor, with 1920 x 1200 resolution.
-----------------------------------------------------
------------------- MAIN EDID BLOCK -----------------
-----------------------------------------------------
EDID Version........1.3
Manufacturer........SAM (4C2D)
Product ID..........2106 (083A)
Serial Number.......30313034
Manufactured........Week 32 of year 2012
Max H Size..........52 cm
Max V Size..........32 cm
Gamma...............2.20
Display Supported Features:
---------------------------
Power Management: Active off
Display type:
-------------
RGB 4:4:4 & YCrCb 4:4:4 Color Encoding Formats
Display is non continuous frequency
Default color space is not sRGB standard
Preferred timing mode includes Native Pixel Format
Input signal & sync:
--------------------
Digital Input
Color Bit Depth is undefined
Digital Interface is not defined
Color info:
-----------
Red x = 0.633 Green x = 0.320 Blue x = 0.155 White x = 0.312
Red y = 0.340 Green y = 0.622 Blue y = 0.042 White y = 0.329
Established Timings:
--------------------
720 x 400 @ 70Hz
640 x 480 @ 60Hz
640 x 480 @ 67Hz
640 x 480 @ 72Hz
640 x 480 @ 75Hz
800 x 600 @ 56Hz
800 x 600 @ 60Hz
800 x 600 @ 72Hz
800 x 600 @ 75Hz
832 x 624 @ 75Hz
1024 x 768 @ 60Hz
1024 x 768 @ 70Hz
1024 x 768 @ 75Hz
1280 x 1024 @ 75Hz
Manufacturer Reserved Timings:
------------------------------
1152 x 870 @ 75Hz
Standard Timing Identification:
-------------------------------
#0: 1152 x 864 @ 75Hz (714F)
#1: 1280 x 800 @ 60Hz (8100)
#2: 1280 x 960 @ 60Hz (8140)
#3: 1280 x 1024 @ 60Hz (8180)
#4: 1440 x 900 @ 60Hz (9500)
#5: 1440 x 900 @ 75Hz (950F)
#6: 1600 x 1200 @ 60Hz (A940)
#7: 1680 x 1050 @ 60Hz (B300)
Monitor Description blocks:
---------------------------
Descriptor #0 - Timing definition:
Mode = 1920 x 1200 @ 59.950Hz
Pixel Clock............. 154.00 MHz Non-Interlaced
Horizontal Vertical
Active.................. 1920 pixels 1200 lines
Front Porch............. 48 pixels 3 lines
Sync Width.............. 32 pixels 6 lines
Back Porch.............. 80 pixels 26 lines
Blanking................ 160 pixels 35 lines
Total................... 2080 pixels 1235 lines
Scan Rate............... 74.038 kHz 59.950 Hz
Image Size.............. 518 mm 324 mm
Border.................. 0 pixels 0 lines
Sync: Digital separate with
* Negative vertical polarity
* Positive horizontal polarity
Descriptor #1 - Monitor limits:
Horizontal frequency range.......30-81 kHz
Vertical frequency range.........56-75 Hz
Maximum bandwidth range..........170 MHz
GTF supported
Descriptor #2 - Monitor name:
SMS24A450
Descriptor #3 - Serial number:
H4MC805185
-----------------------------------------------------
------------ EXTENSION EDID BLOCK 1 ---------------
-----------------------------------------------------
CEA-EXT: CEA 861 Series Extension:
----------------------------------
Revision:..............................1
First DTD block at offset..............0
New Monitor, with 1920 x 1080 resolution.
-----------------------------------------------------
------------------- MAIN EDID BLOCK -----------------
-----------------------------------------------------
EDID Version........1.3
Manufacturer........SAM (4C2D)
Product ID..........2507 (09CB)
Serial Number.......5A583854
Manufactured........Week 9 of year 2015
Max H Size..........53 cm
Max V Size..........30 cm
Gamma...............2.20
Display Supported Features:
---------------------------
Power Management: Active off
Display type:
-------------
RGB 4:4:4 & YCrCb 4:4:4 Color Encoding Formats
Display is non continuous frequency
Default color space is not sRGB standard
Preferred timing mode includes Native Pixel Format
Input signal & sync:
--------------------
Digital Input
Color Bit Depth is undefined
Digital Interface is not defined
Color info:
-----------
Red x = 0.638 Green x = 0.334 Blue x = 0.150 White x = 0.312
Red y = 0.348 Green y = 0.608 Blue y = 0.057 White y = 0.329
Established Timings:
--------------------
720 x 400 @ 70Hz
640 x 480 @ 60Hz
640 x 480 @ 67Hz
640 x 480 @ 72Hz
640 x 480 @ 75Hz
800 x 600 @ 56Hz
800 x 600 @ 60Hz
800 x 600 @ 72Hz
800 x 600 @ 75Hz
832 x 624 @ 75Hz
1024 x 768 @ 60Hz
1024 x 768 @ 70Hz
1024 x 768 @ 75Hz
1280 x 1024 @ 75Hz
Manufacturer Reserved Timings:
------------------------------
1152 x 870 @ 75Hz
Standard Timing Identification:
-------------------------------
#0: 1152 x 864 @ 75Hz (714F)
#1: 1280 x 720 @ 60Hz (81C0)
#2: 1280 x 800 @ 60Hz (8100)
#3: 1280 x 1024 @ 60Hz (8180)
#4: 1440 x 900 @ 60Hz (9500)
#5: 1600 x 900 @ 60Hz (A9C0)
#6: 1680 x 1050 @ 60Hz (B300)
Monitor Description blocks:
---------------------------
Descriptor #0 - Timing definition:
Mode = 1920 x 1080 @ 60.000Hz
Pixel Clock............. 148.50 MHz Non-Interlaced
Horizontal Vertical
Active.................. 1920 pixels 1080 lines
Front Porch............. 88 pixels 4 lines
Sync Width.............. 44 pixels 5 lines
Back Porch.............. 148 pixels 36 lines
Blanking................ 280 pixels 45 lines
Total................... 2200 pixels 1125 lines
Scan Rate............... 67.500 kHz 60.000 Hz
Image Size.............. 531 mm 299 mm
Border.................. 0 pixels 0 lines
Sync: Digital separate with
* Positive vertical polarity
* Positive horizontal polarity
Descriptor #1 - Monitor limits:
Horizontal frequency range.......30-81 kHz
Vertical frequency range.........56-75 Hz
Maximum bandwidth range..........170 MHz
GTF supported
Descriptor #2 - Monitor name:
S24C450
Descriptor #3 - Serial number:
HTLG202112
----------------------------------------------------
------------ EXTENSION EDID BLOCK 1 ---------------
-----------------------------------------------------
CEA-EXT: CEA 861 Series Extension:
----------------------------------
Revision:..............................1
First DTD block at offset..............0
